(一定要简便计算,不能是干算)51*49+3.51*49+3.51*51=?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/10 06:30:17

(一定要简便计算,不能是干算)51*49+3.51*49+3.51*51=?
(一定要简便计算,不能是干算)
51*49+3.51*49+3.51*51=?

(一定要简便计算,不能是干算)51*49+3.51*49+3.51*51=?
51*49+3.51*49+3.51*51
=51×49+3.51×(49+51)
=51×49+3.51×100
=51×49+351
=51×49+51+300
=51×50+50×6
=50×57
=2850

原式=51*49+3.51*100=50*49+49+351=490+400=890

51*49+3.51*49+3.51*51
=(50-1)(50+1)+3.51(49+51)
=2500-1+351
=2500+350
=2850