Thực hiện phép tính
Bài 1: Thực hiện phép tính
A) 7/-25 + -8/25
B) 6/13 + -14/39
C) 4/5+ 4/-18
D) -2 + -5/8
E ) - ( - 1 /21) + 1/28
F) - 8 /18 + - 15 + 27
Bài 2. Tính hợp lý
a) A= - 3 /17 + ( 2/3 + 3/17 )
b) B= -5/21+ ( -16/21 +1)
c) C= -5/7 + 3/4 +1/5 - 2/7 +1/4
d) D= - 3 /31+ -6 /17 + 1/25 + -28/31 +-11/17+-1/5
e) E= 9/11+5/7 + -20/11 + 8/13 + 2/7
f) F = 8/13 + 9/17+ -34/13 + -8 /17
Bài 3 : Tìm x biết
A) x-1/5=2/11
B) x-7/8= 13/12
C).x/5 = 5/6+ 19/30
D) x - - 6 /15 = 4/27
E) x/15 = 3/5 + 2/3
F) 4/6 - x = - 5 / 25 + -7 /15.
A) 7/-25 + -8/25
B) 6/13 + -14/39
C) 4/5+ 4/-18
D) -2 + -5/8
E ) - ( - 1 /21) + 1/28
F) - 8 /18 + - 15 + 27
Bài 2. Tính hợp lý
a) A= - 3 /17 + ( 2/3 + 3/17 )
b) B= -5/21+ ( -16/21 +1)
c) C= -5/7 + 3/4 +1/5 - 2/7 +1/4
d) D= - 3 /31+ -6 /17 + 1/25 + -28/31 +-11/17+-1/5
e) E= 9/11+5/7 + -20/11 + 8/13 + 2/7
f) F = 8/13 + 9/17+ -34/13 + -8 /17
Bài 3 : Tìm x biết
A) x-1/5=2/11
B) x-7/8= 13/12
C).x/5 = 5/6+ 19/30
D) x - - 6 /15 = 4/27
E) x/15 = 3/5 + 2/3
F) 4/6 - x = - 5 / 25 + -7 /15.