五年级简便运算（讲解如何计算）（求讲解） 0.85+0.85×199 11-7÷2.5×0.8 12.5×0.25×3.2 8.71-0.94-（1.71+2.06） 1÷【（1.1-0.7）×0.2】
2019-05-31
五年级简便运算（讲解如何计算）
（求讲解） 0.85+0.85×199 11-7÷2.5×0.8 12.5×0.25×3.2 8.71-0.94-（1.71+2.06） 1÷【（1.1-0.7）×0.2】
优质解答
1 乘法分配律
0.85+0.85×199
=0.85×﹙1+199﹚
=0.85×200
=85×2
=170
2 11-7÷2.5×0.8
=11-2.8×0.8
=11-2.24
=8.76
3 乘法交换、结合律
12.5×0.25×3.2
=12.5×0.8×0.25×4
=10×1
=10
4 加法交换、结合律
8.71-0.94-﹙1.71+2.06﹚
=8.71-1.71-0.94-2.06
=﹙8.71-1.71﹚-﹙0.94+2.06﹚
=7-3
=4
5 1÷[﹙1.1-0.7﹚×0.2]
=1÷[0.4×0.2]
=1÷0.08
=12.5
1 乘法分配律
0.85+0.85×199
=0.85×﹙1+199﹚
=0.85×200
=85×2
=170
2 11-7÷2.5×0.8
=11-2.8×0.8
=11-2.24
=8.76
3 乘法交换、结合律
12.5×0.25×3.2
=12.5×0.8×0.25×4
=10×1
=10
4 加法交换、结合律
8.71-0.94-﹙1.71+2.06﹚
=8.71-1.71-0.94-2.06
=﹙8.71-1.71﹚-﹙0.94+2.06﹚
=7-3
=4
5 1÷[﹙1.1-0.7﹚×0.2]
=1÷[0.4×0.2]
=1÷0.08
=12.5