计算下面各题,能简算的要简算!

1-(3又1/2-2又1/2÷1又1/4)*4/9
=1-(7/2-(5/2)/(5/4))*(4/9)
=1-(7/2-(5/2)*(4/5))*(4/9)
=1-(7/2-(4/2))*(4/9)
=1-(3/2)*(4/9)
=1-(2/3)
=1/3
2000÷5/21-3又1/5*2000
=2000*(1/(5/21)-3又1/5)
=2000*(1*(21/5)-16/5)
=2000*(21/5-16/5)
=2000*(5/5)
=2000
[0.186+(1又3/4-1/2)-0.186-1又1/4]+45
=[(1又3/4-1/2)-1又1/4]+45
=[1又3/4-1/2-1又1/4]+45
=[2/4-1/2]+45
=45
7/10÷(1-3/4*0.4)
=(7/10)/(1-0.3)
=(7/10)/(7/10)
=1
3/8*[(1又1/2+2又2/3)÷5/6-2又1/3]
=3/8*[(3/2+8/3)/(5/6)-7/3]
=3/8*[(3/2+8/3)*6/5-7/3]
=3/8*[(9/6+16/6)*6/5-7/3]
=3/8*[(25/6)*6/5-7/3]
=3/8*[5-7/3]
=3/8*[(15-7)/3]
=3/8*[8/3]
=1
5又3/4*0.4+2/5*4.25
=23/4*0.4+2/5*4.25
=2.3+2*0.85
=2.3+1.7
=4
2.7*2.75+6.3*2.75+2又3/4
=(2.7+6.3)*2.75+11/4
=9*2.75+11/4
=24.75+2.75
=27.5
(3又5/12-1又2/7)-(1又4/7-1又7/12)
=(41/12-9/7)-(11/7-19/12)
=41/12-9/7-11/7+19/12
=41/12+19/12-9/7-11/7
=60/12-20/7
=420/84-240/84
=180/84
=45/21
=15/7
42又14/15÷7
=(42又14/15)/7
=(42/7)又((14/15)/7)
=6又(2/15)