Question

0.78×0.8的简便方法

Answer 1

0.78×0.8
=0.78×（1－0.2）
=0.78×1－0.78×0.2
=0.78－0.156
=0.624

Answer 2

0.78×0.8
＝（0.7＋0.08）×0.8
＝0.7×0.8＋0.08×0.8
＝0.56＋0.064
＝0.624

Answer 3

0.78×0.8
＝（0.7＋0.08）×0.8
＝0.7×0.8＋0.08×0.8
＝0.56＋0.064
＝0.624

Answer 4

1.78×8=624 先按照整数乘法的计算法则算出积，再看因数中共有几位小数，就从积的右边起数出几位。所以答案是0.624
2.0.78×0.8 =0.78×(1-0.2) =0.78×1-0.78×0.2 =0.78-0.156 =0.624

Answer 5

0.78×0.8 =0.78×(1-0.2) =0.78×1-0.78×0.2 =0.78-0.156 =0.624