Tài liệu 10 đề thi học sinh giỏi toán lớp 3

10 đề thi học sinh giỏi toán lớp 3 §Ò 1 1. TÝnh nhanh: a) 75 - 13 - 17 + 25 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... b) 10 - 9 + 8 - 7 + 6 - 5 + 4 - 3 + 2 - 1 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 2. T×m x: a) X + 15 = 15 - X b) 5 x X = 5 : X ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 3. T×m sè cã hai ch÷ sè, biÕt tÝch c¸c ch÷ sè cña sè ®ã lµ 0 vµ tæng c¸c ch÷ sè cña sè ®ã lµ 8. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ............................................................................... 4. Mai cã 28 b«ng hoa, Mai cho Hoµ 8 b«ng hoa, Hoµ l¹i cho Hång 5 b«ng hoa. Lóc nµy ba b¹n ®Òu cã sè b«ng hoa b»ng nhau. Hái lóc ®Çu, Hoµ vµ Hång mçi b¹n cã bao nhiªu b«ng hoa? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ...................................................................... 5. Mét con èc sªn bß tõ ch©n lªn ®Ønh mét c¸i cét cao 10 m. Ban ngµy sªn bß lªn ®îc 5m, nhng ban ®ªm nã l¹i tôt xuèng 40dm. Hái muèn bß lªn tíi ®Ønh cét, con sªn ph¶i bß mÊy ngµy, mÊy ®ªm? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................. 6. C¸c c¹nh cña mét h×nh tø gi¸c cã ®é dµi b»ng nhau. Chu vi h×nh tø gi¸c lµ 40dm. TÝnh ®é dµi mçi c¹nh? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ...................................................................... §Ò 2 1. TÝnh nhanh: a) 10 +10 + 10 - 4 - 3 - 2 - 1 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... b) 20 + 19 + 12 + 8 + 4 - 18 - 14 - 10 - 6 - 2 +1 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 2. T×m y: a) 34 + 6 - Y = 45 - 7 b) Y - 1 - 2- 3- 4 = 5 - 6 + 7 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 3. Hai sè cã tæng b¨ng 386 nÕu gi÷ nguyªn sè thø nhÊt vµ thªm vµo sè thø hai mét sè b»ng sè thø nhÊt th× ®îc tæng míi lµ 497. T×m hai sè ®ã. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. .............................................................................. 4. HiÖn t¹i, tuæi «ng vµ tuæi ch¸u céng l¹i lµ 76 tuæi. Hái sau ba n¨m n÷a, tuæi «ng vµ tuæi ch¸u céng l¹i lµ bao nhiªu tuæi? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ............................................................................... 5. Ngµy 12 th¸ng 8 lµ ngµy thø t. Hái th¸ng 8 ®ã cã mÊy ngµy thø t? ®ã lµ nh÷ng ngµy nµo? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ...................................................................... 6. H·y so s¸nh chu vi h×nh vu«ng ABCD víi tæng chu vi 3 h×nh vu«ng: h×nh vu«ng 1, h×nh vu«ng2, h×nh vu«ng 3. 2 1 3 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. .......................... §Ò 3 1)TÝnh nhanh a)1 + 2 + 3 + 4 +....... + 9 + 10 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... b)76 + 78 + 80 - 70 - 68 - 66 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 2)T×m x a)354 - x + 457 = 568 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... b)978 - 459 - x - 234 = 87 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 3)Cho tÝch 14 x X . NÕu t¨ng x thªm 2 ®¬n vÞ th× kÕt qu¶ cña tÝch 14 x X t¨ng thªm bao nhiªu ®¬n vÞ ? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. .............................................................................. 4) Cho 3 ch÷ sè 0 , 2 , 4 . Hái lËp ®îc bao nhiªu sè cã 3 ch÷ sè kh¸c nhau tõ 3 ch÷ sè ®· cho ? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ............................................................................... 5) Hai ®éi bãng bµn, mçi ®éi cã 3 ngêi ch¬i ®Êu bãng bµn víi nhau. Mçi ngêi cña ®éi nµy ®Òu ®Êu 1 v¸n víi mçi ngêi cña ®éi kia. Hái cã tÊt c¶ bao nhiªu v¸n ®Êu? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. .......................... 6)TÝnh chu vi cña 1 h×nh tam gi¸c ABC. BiÕt tæng ®é dµi cña c¹nh AC vµ c¹nh AB lµ 17 cm, c¹nh BC lµ 6 cm. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ............................................................. §Ò 4 1.TÝnh b»ng c¸ch thuËn tiÖn nhÊt: a) 11 + 22 + 33 + 44 + 55 + 66 + 77 + 88 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... b) 15 x 2 + 15 x 3 + 15 x 5 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. .................................. 2. T×m X: a) x - 16 + 4 = 32 + 20 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... b) 476 - 239 < x + 123 - 36 < 239 ........................................................................................... ................................................................................................. ................................................................................................. ................................................................................................. ......................................... 3. T×m hai sè cã th¬ng b»ng 0 vµ tæng b»ng 52. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 4. B¸c Lan ®em ®i chî b¸n 56 qu¶ trøng gµ vµ 75 qu¶ trøng vÞt. Däc ®êng b¸c ®· b¸n mét sè trøng gµ vµ mét sè trøng vÞt. §Õn chî b¸c b¸n 1/ 4 sè trøng gµ vµ 1/ 5 sè trøng vÞt th× võa hÕt. Hái däc ®êng ®· b¸n ®îc bao nhiªu qu¶ trøng gµ? bao nhiªu qu¶ trøng vÞt? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ...................................................................... 5. Mét tê b×a h×nh ch÷ nhËt cã chu vi gÊp ®«i chu vi tê b×a h×nh vu«ng c¹nh 45 cm. TÝnh chiÒu dµi vµ chiÒu réng tê b×a h×nh ch÷ nhËt ®ã, biÕt chiÒu dµi gÊp 4 lÇn chiÒu réng? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ........................................... §Ò5 1. TÝnh nhanh a) 64 x 5 + 18 x 5 + 18 x 5 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... b) 12 x 3 + 36 x 2 + 12 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 2. T×m y: a) 15 + 36 : y = 24 b) y x 7 + 134 = 288 .......................................................................................... ................................................................................................. ................................................................................................. ................................................................................................. .......................................... 3. T×m sè bÞ chia, biÕt th¬ng lµ 6 vµ sè chia lµ sè lín nhÊt cã thÓ cã. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 4. Hai sè cã hiÖu b»ng 38. NÕu lÊy sè lín chia cho sè bÐ th× ®îc th¬ng lµ 5 vµ sè d lµ 2. T×m hai sè ®ã? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 5. C« gi¸o cã 192 viªn kÑo chøa ®Òu trong hép, c« lÊy ra mçi hép 9 viªn kÑo ®Ó chia cho c¸c ch¸u thiÕu nhi, sau khi chia c« gi¸o cßn l¹i 120 viªn kÑo. Hái tríc khi chia mçi hép cã bao nhiªu viªn kÑo? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 6. Mét h×nh ch÷ nhËt cã chu vi 870cm. TÝnh chiÒu dµi vµ chiÒu réng h×nh ®ã, biÕt r»ng chiÒu dµi gÊp 4 lÇn chiÒu réng? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... §Ò 6 1. §iÒn dÊu ( <, >, =) thÝch hîp vµo chç trèng. a) 32 - 14 : 2 16 + 8 x 2 b) 42 : 3 x 4 2. T×m x: a) 199 < xxx 72 x 4 : 6 < 299 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 3. T×m sè bÞ chia vµ sè chia bÐ nhÊt sao cho phÐp chia cã th¬ng b»ng 15 vµ sè d lµ 7. ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 4. Häc sinh líp 3A tham gia lao ®éng tíi c©y trong vên trêng. C« gi¸o giao cø 5 em th× tíi 25 c©y, nhng thùc tÕ mçi em l¹i tíi nhiÒu h¬n nhiÖm vô ®îc giao lµ 2 c©y, nªn tæng sè c©y tíi ®îc lµ 238 c©y. Hái líp 3A cã bao nhiªu häc sinh? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 5. Cho h×nh vu«ng MNPQ cã c¸c c¹nh b»ng 10cm vµ A, B, C, D lÇn lît lµ trung ®iÓm cña c¸c c¹nh MN, NP, PQ, QM. H·y tÝnh tæng chu vi cña tÊt c¶ c¸c h×nh vu«ng cã ë h×nh bªn. M 0 A D Q N B C P ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... §Ò 7 1. TÝnh gi¸ trÞ biÓu thøc: 88: 4 + 236 303 - 56 : 7 27 : 3 x 5 - 5 54 : 6 x 5 + 93 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 2. T×m x: a) 27 : 9 x X = 3 b) 93 - ( x+ 3) = 13 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 3. N¨m nay mÑ t«i 38 tuæi. Sang n¨m, tu«it\r anh t«i b»ng 1 3 tuæi mÑ t«i. Hái mÑ t«i sinh anh t«i n¨m mÑ t«i bao nhiªu tuæi? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 4. Cã mét c©n hai ®Üa vµ 3 qu¶ c©n gåm c¸c lo¹i: 1kg, 2kg, 3 kg . Hái cã bao nhiªu c¸ch c©n mµ chØ c©n mét lÇn lÊy ra ®îc 4 kg ®êng? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 5. Mét h×nh ch÷ nhËt cã chu vi b»ng 5 lÇn chiÒu réng. BiÕt chiÒu dµi b»ng 60 cm. TÝnh chu vi h×nh ch÷ nhËt? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... §Ò 8 1. Kh«ng tÝnh gi¸ trÞ cña biÓu thøc h·y ®iÒn dÊu (>, <, =) thÝch hîp vµo « trèng: a) 156 x 6 x7 6 x 156 x 7 ................................................................................................ ................................................................................................. ................................................................................................. ................................................................................................. .................................... b) 198 : 3 x 8 189 : 9 x 8 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 2. T×m y: a) y : 8 = 5 ( d7) b) 72 - x : 4 = 16 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 3. Thªm dÊu ngoÆc ®¬nvµo biÓu thøc sau ®©y®Ó ®îc biÓu thøc míi cã gi¸ trÞ b»ng 22. 3+8 x4-2 ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 4. Bao thø nhÊt cã 12 kg g¹o, bao thø hai cã sè g¹o gÊp 3 lÇn bao thø nhÊt. Hái ph¶i chuyÓn tõ bao thø hai sang bao thø nhÊt bao nhiªu kg ®Ó sè g¹o ë hai bao b»ng nhau? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... 5. Mét h×nh ch÷ nhËt cã chiÒu réng b»ng 1 3 chiÒu dµi, biÕt r»ng nÕu t¨ng chiÒu réng thªm 14cm th× ®îc mét h×nh vu«ng. T×m diÖn tÝch cña h×nh ch÷ nhËt? ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ................................... ................................................................................................. ................................................................................................. ................................................................................................. ................................................................................................. ...................................