Question

98.6×98.6-98.5×98.7＝?要简便计算

Answer 1

98.6*98.6-98.5*98.7

=98.6*98.6-98.5*(98.6+0.1)

=98.6*98.6-98.5*98.6-9.85

=98.6*(98.6-98.5)-9.85

=9.86-9.85

=0.01

小数乘法的运算法则：

1、先按照整数乘法的法则求出积。

2、再看被乘数和乘数一共有几位小数，就从积的右边起数出几位，点上小数点。

3、如果小数的末尾出现0时，根据小数的基本性质，把小数末尾的0划去。

Answer 2

98.6*98.6-98.5*98.7
=98.6*98.6-98.5*(98.6+0.1)
=98.6*98.6-98.5*98.6-9.85
=98.6*(98.6-98.5)-9.85
=9.86-9.85
=0.01