Đáp án:
Giải thích các bước giải:
Bài 1:
1)A= 7/12+ 5/6 - (-1/4) - 3/7 + (-5/7)
A= 7/12+5/6+1/4-3/7-5/7
A= (7/12+1/4+5/6)-(3/7+5/7)
A= (7/12+3/12+10/12)- 8/7
A= 5/3-8/7=11/21
2)B= (21/31+ âm 16/7)+(44/53+ 10/31) + 9/53
B= 21/31-16/7+44/53+10/31+9/53
B= (21/31+10/31)+(44/53+9/53)-16/7
B= 1+1-16/7=-2/7
3) C= 2/7+ (-3/8)+ 4/7+1/7+ (-1/8)
C= 2/7-3/8+ 4/7+1/7-1/8
C= (2/7+1/7+4/7) -(3/8+1/8)
C= 1- 1/2=1/2
4) D= (1/3 + âm 3/4 +3/5)-(1/36 trừ 1/57+ âm 1/15) + âm 2/9
D= 1/3-3/4+3/5-1/36-1/57+1/15-2/9
D= (1/3+3/5+1/15)-(3/4+1/36)-1/57-2/9
D= 1- 7/9 -1/57-2/9
D= 1-1/57-(7/9+2/9)
D= 56/57 -1= -1/57
5) E=19/24 - 1/2 - 1/3 +(- 7/24)
E=(19/24-1/2-7/24) -1/3
E=0-1/3= -1/3
6) F=-1/2 +3/5 - 1/9+ 1/127+ (- 7/18) - (-4/35) + 2/7
F=-1/2 +3/5 - 1/9+ 1/127- 7/18 +4/35 + 2/7
F= -(1/2+1/9+7/18)+(3/5+4/35+2/7)+1/127
F= -1+1+1/127 =1/127