0.64*25*7.8+2.2这道题用简便方法应该怎么做
问题描述：
0.64*25*7.8+2.2这道题用简便方法应该怎么做
答
0.64*25*7.8+2.2
=4×0.16×25×7.8+2.2
=（4×25）×0.16×7.8+2.2
=100×0.16×7.8+2.2
=16×7.8+2.2
=15×7.8+7.8+2.2
=15×（8-0.2）+10
=15×8-15×0.2+10
=120-3+10
=127