Question

Dạng 1. Thực hiện phép tính (tính nhanh nếu có thể)

a) 1/2 + 3/4 - (3/4 - 4-5)

b) (9/16 + 8/-27) - (19/27 - 7/16 - 2)

c) - 5/8 . (4/9 + 7/-12)

d) 7/10 . -3/5 + 7/10 . -2/5 -  -3/10

e) -3/7 . 5/9 + 4/9 . -3/7 + 2 3/7

f) 8 2/7 - (3 4/9 + 4 2/7)

h) 3 . (-1/2 )^2 - (4/5 + 8/15) : 5/6 

 các bạn giúp mình nha!!

Answer 1

a) 1/2 + 3/4 - (3/4 - 4 - 5)

= 1/2 + 3/4 - 3/4 + 4 + 5

= (3/4 - 3/4) + (4 + 5) + 1/2

= 0 + 9 + 1/2

= 19/2

b) [9/16 + 8/(-27)] - (19/27- 7/16 - 2)

= 9/16 - 8/27 - 19/27 + 7/16 + 2

= (9/16 + 7/16) + (-8/27 - 19/27) + 2

= 1 - 1 + 2

= 2

c) -5/8 . [4/9 + 7/(-12)]

= -5/8 . (-5/36)

= 25/288

d) 7/10 . (-3/5) + 7/10 . (-2/5) - (-3/10)

= 7/10 . (-3/5 - 2/5) + 3/10

= 7/10 . (-1) + 3/10

= -2/5

e) -3/7 . 5/9 + 4/9 . (-3/7) + 2 3/7

= -3/7 . (5/9 + 4/9) + 17/7

= -3/7 . 1 + 17/7

= 2

f) 8 2/7 - (3 4/9 + 4 2/7)

= 8 + 2/7 - 3 - 4/9 - 4 - 2/7

= (8 - 3 - 4) + (2/7 - 2/7) - 4/9

= 1 - 4/9

= 5/9

h) 3.(-1/2)² - (4/5 + 8/15) : 5/6

= 3.1/4 - 4/3 : 5/6

= 3/4 - 8/5

= -17/20

Answer 2

DAI QUA .