Câu 3 : thực hiện phép tính

a) 2/3+1/3×(-4/9+5/6):7/12

b) 6/7+5/8:5-3/16×(-4)

c) -4/7-5/13×-39/25+-1/42:(-5/6)

d)6/7:(2/5×6/7)

e) 6/7+5/7:5-8/9

g) 6/7+5/8×1/5-3/16×4

I) -1/6+2/3×-3/4+4/5

k) -1/3×7/24:14/36

L) 5/4-1/2+-7/8

M) -3/14+5/8-1/2

N) 5/23×(13/5-14/4)

Đáp án + Giải thích các bước giải:
Câu 3: Thực hiện phép tính

a) `2/3 + 1/3 xx (-4/9 + 5/6) : 7/12`

`= 2/3 + 1/3 xx (-4/9 + 10/9) : 7/12`

`= 2/3 + 1/3 xx 2/3 : 7/12`

`= 2/3 + 2/9 : 7/12`

`= 2/3 + 4/27 : 7/12`

`= 2/3 + 4/27 xx 12/7`

`= 2/3 + 16/27`

`= 14/27`

b) `6/7 + 5/8 : 5 - 3/16 xx (-4)`

`= 6/7 + 5/8 : 5 + 3/4`

`= 6/7 + 5/8 xx 4/5 + 3/4`

`= 6/7 + 1/2 + 3/4`

`= 12/14 + 7/14 + 10/14`

`= 29/14`

c) `-4/7 - 5/13 xx -39/25 + -1/42 : (-5/6)`

`= -4/7 + 15/13 + 1/42 x 6/5`

`= -4/7 + 15/13 + 1/7`

`= -4/7 + 16/13`

`= -56/91 + 112/91`

`= 56/91`

d) `6/7 : (2/5 xx 6/7)`

`= 6/7 : 12/35`

`= 6/7 xx 35/12`

`= 35/14`

e) `6/7 + 5/7 : 5 - 8/9`

`= 11/7 : 5 - 8/9`

`= 11/7 xx 1/5 - 8/9`

`= 11/35 - 8/9`

`= 99/315 - 272/315`

`= -173/315`

g) `6/7 + 5/8 xx 1/5 - 3/16 xx 4`

`= 6/7 + 1/8 - 3/4`

`= 48/56 + 7/56 - 42/56`

`= 13/56`

i) `-1/6 + 2/3 xx -3/4 + 4/5`

`= -1/6 - 1/2 + 4/5`

`= -5/30 - 15/30 + 24/30`

`= 14/30`

k) `-1/3 xx 7/24 : 14/36`

`= -7/72 : 7/18`

`= -7/72 xx 18/7`

`= -18/72`

`= -1/4`

l) `5/4 - 1/2 + -7/8`

`= 10/8 - 4/8 + -7/8`

`= 3/8`

m) `-3/14 + 5/8 - 1/2`

`= -3/14 + 10/14 - 7/14`

`= 0/14`

n) `5/23 xx (13/5 - 14/4)`

`= 5/23 xx (26/5 - 35/5)`

`= 5/23 xx (-9/5)`

`= -45/115`