Question

8.9×6.5+8点9+2.5怎么做才能简便？

Answer 1

8.9×6.5+8.9×2.5
＝8.9×(6.5+2.5)
＝8.9×9
＝8.9×10-8.9
＝89-8.9
＝80.1

Answer 2

＝8.9×6.5+8.9×1+2.5
＝8.9×（6.5+1）+2.5
＝8.9×7.5+2.5
＝（9-0.1）×7.5+2.5
＝67.5-0.75+2.5
＝70-0.75
＝69.25

Answer 3

8.9×6.5+8.9+2.5。因为式子中有加法也有乘法，按照运算规则只能先计算乘法，在计算加法。

Answer 4

这个算式简便算法是提取公因数
8.9×6.5+8.9×2.5
=8.9×（6.5+2.5）
=8.9×9
=80.1很简便可以口算

Answer 5

8.9×6.5+8.9+2.5
=8.9×（6.5+1）+2.5
=8.9×7.5+2.5
=8.9×3×2.5+2.5
=2.5×（8.9×3+1）
=2.5×（26.7+1）
=2.5×27.7
=69.25