752×1.25+4.45×12.5+0.035×125
=(75.2+4.45+0.35)×12.5
=80×12.5
=1000
0.42×160+36×1.6-31×3.2
=42×1.6+36×106-31×2×1.6
=(42+36-62)×1.6
=6×1.6
=9.6
1.625+2.625+3.625+……+79.625+80.625
=40×80+0.625
=3200+0.625
=3200.625
(1)原式=752*1.25+44.5*1.25+3.5*1.25=800*1.25=1000
(2)原式=42*1.6+36*1.6-62*1.6=16*1.6=25.6
(3)原式=(1+2+3+···+79+80)+0.625*80=(80+1)*40+50=3290
第一个,把125的小数点统一,使他都成为1.25
第一题1.25×752+1.25×44.5+1.25×3.5=1.25×(752+44.5+3.5)