Question

（-2）-12-（+4）列式计算

Answer 1

5/6+1/2+2/3
=5/6+3/6+4/6
=12/6
=2
17/12-3/4-1/3
=17/12-9/12-4/12
=1/12(17-9-4)
=4/12
=1/3
5分之4-6分之1＋2分之1,
4/5-1/6+1/2
=4/5-1/6+3/6
=12/15-5/15
=7/15
20分之9＋3分之1＋20分之11
9/10+1/3+11/20
=18/10+11/20+1/3
=29/20+1/3
=87/60+20/60
=107/60
,9分之8＋5分之4-9分之8,
8/9+4/5-8/9
=8/9-8/9+4/5
=0+4/5
=4/5
5分之2＋8分之1＋8分之7,
2/5+1/8+7/8
=2/5+1
=7/5
7分之2＋6分之5-2分之1,
2/7+5/6-1/2
=2/7+5/6-3/6
=2/7+1/3
=6/21+7/21
=13/21
6分之1＋4分之3＋3分之1
1/6+3/4+1/3
=2/12+9/12+4/12
=15/12
=5/4