简便方法计算 1.625+2.625+3.625+······+79.625+80.625

题目

简便方法计算 1.625+2.625+3.625+······+79.625+80.625
简便方法计算以下各题：752*1.25+4.45*12.5+0.035*125
0.4*160+36*1.6-31*3.2
1.625+2.625+3.625+······+79.625+80.625（写出过程）

答案