Question

36×2.57+1.2×22.9怎么简便运算？

Answer 1

=1.2x（30x2.57）+1.2x22.9

=1.2x（77.1+22.9）

=1.2x100

=120

Answer 2

解:
36×2.57+1.2×22.9
=1.2×30×2.57+1.2×22.9
=1.2×77.1+1.2×22.9
=1.2×（77.1+22.9）
=1.2×100
=120

Answer 3

36×2.57+1.2×22.9
=12x3x2.57+12x2.29
=12x7.71+12x2.29
=12x（7.71+2.29）
=12x10
=120
乘法分配律是一种简算定律：两个数的和与一个数相乘，可以先把它们分别与这个数相乘，再相加，得数不变，这叫做分配律。

Answer 4

原式＝1.2×30×2.57+1.2×22.9
＝1.2×77.1+1.2×22.9
＝1.2×（77.1+22.9）
＝1.2×100
＝120

Answer 5

=1.2×30×2.57+1.2×22.9
=1.2×30×(2.5+0.07)+1.2×22.9
=1.2×(75+2.1+22.9)
=1.2×100
=120