二又五分之四乘7.45加2.8乘而又二十分之十一
=2.8×7.45+2.8×2.55
=2.8×(7.45+2.55)
=2.8×10
=28再问一题： 0.375×4又3/8－3/8＋15.625×37.5%，好人帮到底，谢了0.375×4又3/8－3/8＋15.625×37.5%

=0.375×4.375-0.375+15.625×0.375
=0.375×(4.375+15.625)-0.375
=0.375×20-0.375
=7.125