Question

8/15×7/17 ＋7/15×9/17怎样巧算？

Answer 1

解:

原式

=7/15x8/17+7/15x9/17

=7/15x(8/17+9/17)

=7/15x1

=7/15

方法:

构造后利用乘法分配律实现简便计算。

Answer 2

通过加括号来进行简便计算，如下：
8/15x7/17+7/15x9/17
=7/15x8/17+7/15x9/17
=7/15x(8/17+9/17)
=7/15x17/17
=7/15x1
=7/15

Answer 3

8/15×7/17+7/15×9/17
=8/15×7/17+7/17×9/15
=7/17×（8/15+9/15）
=7/17×17/15
=7/15

Answer 4

8/15×7/17+7/15×9/17
=1/15×1/17×(56+63)
=1/15×1/17×119
=1/15×7
=7/15

Answer 5

解:简便运算如下:
8/15x7/17+7/15x9/17
=7/15x8/17+7/15x9/17
=7/15x(8/17+9/17)
=7/15x17/17
=7/15x1
=7/15