Mong các dân toán làm hộ em

Đáp án:

Giải thích các bước giải:

 1) (-4/7+4/7)-14/56=0-1/2=-1/2

2)  12/60+(-1/5-2,75)-0,25=[1/5+(-1/5)]-(2,75+0,25)=0-3=-3

3) -3/5+(-3/7)+1/3+(-2/5)+10/7=[-3/5+(-2/5)]+1/3++[10/7+(-3/7)]=-1+1/3+1=1/3

4) 8/19+(-15/17)+4/23-2/7+11/19=(8/19+11/19)+[(-15/17)-2/7]+4/23=1+(-1)+4/23=4/23

5) 1/2-(-1/3)+1/23+1/6=(3/6+2/6)+1/6+1/23=5/6+1/6+1/23=1+1/23=23+1/23=24/23

6) 1/3-1/7+3/2+17/3-27/7=(1/3+17/3)-(1/7+27/7)+3/2=18/3-28/7+3/2=6-4+3/2

=2+3/2=4+3/2=7/2

7) 15/7-(1/2-5/2)=15/8-(-2)=15/8+16/8=21/8

8) 1/12-(1/6-1/4)=1/12-1/6+1/4=1/12-2/12+3/12=2/12=1/6

9) 1/2-(1/3+1/10)=(1/2-1/10)-1/3=(5/10-1/10)-1/3=2/5-1/3=6/15-5/15=1/15

10) 2/3-5/6+1/12=8/12-10/12+1/12=-1/12

11) 2/3-5/6+1/12=8/12-10/12+1/12=-1/12

12) 7/12+3/8-1/4=14/24+9/24-6/24=17/24