65×20+35×80怎么简算?
问题描述:
65×20+35×80怎么简算?
答
(70-5)*20+(40-5)*80
答
(60+5)*20+(30+5)*80
=1200+100+2400+400
=4100
答
65 × 20 + 35 × 80
= 65 × 20 + 35 × 4 × 20
= 65 × 20 + 140 × 20
= (65 + 140)× 20
= 205 × 20
= 4100