Question

5.8×7.9+21×0.42的简便算法？

Answer 1

简便计算过程如下：

1、提取原式：5.8×7.9+21×0.42

2、计算过程：

      =5.8×7.9+21×0.42

      =(5.8×8-5.8×0.1)+(20×0.42+0.42)

      =(46.4-0.58)+(8.4+0.42)

      =45.82+8.82

      =54.64

3、计算结果：54.64

Answer 2

5.8×7.9+21×0.42
=5.8×7.9+2.1×4.2
=5.8×7.9+2.1×5.8-2.1*1.6
=5.8*（7.9+2.1）-2*1.6-0.1*1.6
=5.8*10-3.2-0.16
=58-3.36
=54.64

Answer 3

5.8×7.9+21×0.42的简便算法？
5.8×7.9+21×0.42
=5.8*7.9+（100-79）*0.42
=5.8*7.9+100*0.42-7.9*4.2
=（5.8-4.2）*7.9+42
=54.64

Answer 4

5.8×7.9+21×0.42
＝45.82+8.82
＝54.64

Answer 5

5×7.9+0.8×7.9+21×0.4+21×0.02=38.5+6.32+8.4+0.42=53.64