（怎样简便就怎样算）①40*25%+18*四分之一+42*0.25②（五分之二+二十五分之二+20%）*25③76*5.

1.原式=40*25%+18*25%+42*25%
=（40+18+42）*25%
=100*25%
=25
2.原式=2/5*25+2/25*25+1/5*25
=10+2+5
=17
3.你一定打错了
4.原式=78/5 /12%+80/12%+75%/12%
=130+2000/3+6.25
=802又11/12