一、用简便方法计算.、1、38.75-15.38+61.25-4.62 2、5/2×6.6+2.5×33/5 3、35/5+2.25+45/8+31/4请详细解答.

问题描述:

一、用简便方法计算.、1、38.75-15.38+61.25-4.62 2、5/2×6.6+2.5×33/5 3、35/5+2.25+45/8+31/4
请详细解答.

(38.75+61.25)-(15.38+4.62)= 100 - 20 = 80
5/2 x 33/5 x 2 = 33
280/40+90/40+225/40+310/40 = 905/40 = 181/8