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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Bài 3: Tính nhanh a) 67. 189 – 67. 45 + 144. 133 b) 394. 1768 + 606. 1769 + 394

Toán Lớp 6: Bài 3: Tính nhanh
a) 67. 189 – 67. 45 + 144. 133 b) 394. 1768 + 606. 1769 + 394
c) 1876. 31 + 56. 124 + 25. 1876 d) 2021. 7615 + 2022. 2385 – 1355
e) ( 565656. 79 – 797979. 56 ) 1.2 + 2.3 + 3.4 + … + 99.100)

Comments ( 1 )

  1. $a$) $ 67. 189 – 67. 45 + 144. 133$
    $= 67(189 – 45) + 144 . 133$
    $= 67.144 + 144.133$
    $= 144(67+133)$
    $= 144 . 200$
    $= 28800$.
    $b$) $394.1768 + 606 . 1769 + 394$
    $= 394(1768 + 1) + 606 . 1769$
    $= 394 . 1769 + 606. 1769$
    $= 1769(394+606)$
    $= 1769.1000$
    $= 1769000$.
    $c$) $1876. 31 + 56. 124 + 25. 1876$
    $= 1876.(31+25) + 56.124$
    $= 1876.56 + 56.124$
    $= 56.(1876 + 124)$
    $= 56.2000$
    $= 112000$.
    $d$) $2021. 7615 + 2021. 2385 – 1355$
    $= 2021(7615+2385) – 1355$
    $= 2021.10000 – 1355$
    $= 20210000 – 1355$
    $= 20208645$.
    $e$) $( 565656. 79 – 797979. 56 ) (1.2 + 2.3 + 3.4 + … + 99.100)$
    $= (10101.56.79 – 79.56.10101)(1.2 + 2.3 + 3.4 + … + 99.100)$
    $= 0.(1.2 + 2.3 + 3.4 + … + 99.100)$
    $= 0$.
     

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222-9+11+12:2*14+14 = ? ( )

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