简便计算.1.5×102= 0.25×32×1.25= 0.36×0.99+0.36×0.01= 2.5×7.2=

9个回答

  • 解题思路:①1.5×102,意义乘法分配律简算;

    ②0.25×32×1.25,把32 拆分为:4×8,然后意义乘法结合律简算;

    ③0.36×0.99+0.36×0.01,意义乘法分配律简算;

    ④2.5×7.2,转化为:2.5×4×1.8,意义乘法结合律简算.

    ①1.5×102

    =1.5×100+1.5×2

    =150+3

    =153;

    ②0.25×32×1.25

    =(0.25×4)×(8×1.25)

    =1×10

    =10;

    ③0.36×0.99+0.36×0.01

    =0.36×(0.99+0.01)

    =0.36×1

    =0.36;

    ④2.5×7.2

    =(2.5×4)×1.8

    =10×1.8

    =18.

    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: 此题考查的目的是理解掌握乘法的运算定律,并且能够灵活运用乘法的运算定律进行简便计算.