(2014•广州模拟)计算下列各题,能简便的请用简便方法

1个回答

  • 解题思路:(1)根据乘法分配律进行简算;

    (2)根据乘法分配律进行简算;

    (3)根据乘法结合律进行简算;

    (4)根据乘法分配律进行简算.

    (1)

    4

    7×23

    12

    13+

    4

    1

    13+16×

    1

    7

    =

    4

    7×(23

    12

    13+

    1

    13)+4×4×

    1

    7

    =

    4

    7×24+4×

    4

    7

    =

    4

    7×(24+4)

    =

    4

    7×28

    =16;

    (2)41.2×3.6+16×1

    1

    4+53.7×6.4

    =41.2×3.6+20+53.7×6.4

    =41.2×(10-6.4)+20+53.7×6.4

    =41.2×10-41.2×6.4+20+53.7×6.4

    =412+20+53.7×6.4-41.2×6.4

    =432+(53.7-41.2)×6.4

    =432+12.5×8×0.8

    =432+80

    =512;

    (3)0.78÷2.6×1.8÷0.12

    =(0.78÷2.6)×(1.8÷0.12)

    =0.3×15

    =4.5;

    (4)12.6×125%+3

    2

    4

    5

    =12.6×1.25+3

    2

    5×1.25

    =(12.6+3

    2

    5)×1.25

    =16×1.25

    =1×(8×1.25)

    =20.

    点评:

    本题考点: 运算定律与简便运算.

    考点点评: 完成本题要注意分析式中数据,运用合适的简便方法计算.