初一有理数的运算题

(-15.5)+(-33.2)-(-42.5)-(+24.8)
=-15.5-33.2+42.5-24.8
=-48.7+42.5-24.8
=-6.2-24.8
=-31

-1/2-6又1/5-1+4又1/5-4.5+3又1/3
=-15/30-186/30-30/30+126/30-135/30+100/30
=(-15-186-30+126-135+100)/30
=-140/30
=-14/3

0-(-1/2)-(-1/3)-(-1/4)-(+1/5)
=1/2+1/3+1/4-1/5
=30/60+20/60+15/60-12/60
=(30+20+15-12)/60
=53/60

|-0.5|-[|(-2)-(+9)|-|-7-5+12|]
=0.5-[|-2-9|-0]
=0.5-11
=-10.5

(-15)-(-5)-(+5)-(-10)
=-15+5-5+10
=-5

(-1/3)-(-1/2)-(-1/6)-(-1又2/3)
=-1/3+1/2+1/6+1又2/3
=-2/6+3/6+1/6+10/6
=(-2+3+1+10)/6
=2

(1) 原式=-15.5-33.2+42.5-24.8=-31
(2) 原式=-0.5-6.2-1+4.2-4.5+3又3/1=-11/3
(3) 原式=1/2+1/3+1/4-1/5=53/60
(4) 原式=0.5-7=6.5
(5) 原式=-15+5-5+10=-5
(6) 原式=-1/3+1/2+1/6+5/3=8/3

解:1.原式=-15.5-33.2+42.5-24.8
=-48.7+42.5-24.8
=-6.2-24.8
=-31
2.原式=-15/30