计算下面各题,能用简便算法的用简便算法

1个回答

  • 解题思路:(1)运用加法交换、结合律,先算12.25+0.85,进而得解;

    (2)运用乘法分配律进行简算;

    (3)先算括号里面的,再算括号外面的;

    (4)运用乘法交换、结合律进行简算;

    (5)先算除法,再算减法.

    (1)12.25-3.1+0.85-6.17,

    =(12.25+0.85)-3.1-6.17,

    =13.1-3.1-6.17,

    =3.83;

    (2)2.65×1.7+1.35×1.7,

    =(2.65+1.35)×1.7,

    =4×1.7,

    =6.8;

    (3)3.6÷(1.2+0.5)×5,

    =3.6÷1.7×5,

    =[36/17]×5,

    =10

    10

    17;

    (4)0.125×0.38×80,

    =(0.125×80)×0.38,

    =10×0.38,

    =3.8;

    (5)21.36÷0.8-12.9,

    =26.7-12.9,

    =13.8.

    点评:

    本题考点: 运算定律与简便运算;小数四则混合运算.

    考点点评: 此题考查小数的四则混合运算,能简算的,灵活的运用运算定律进行简算.