Làm hết giúp mk nhé cảm ơn đúng vào

Đáp án + Giải thích các bước giải:

 Bài 1: Thực hiện phép tính:

a, `(136/15 - 28/5 + 62/10) . 21/24`

` = ( 272/30 - 168/30 + 192/30) . 7/8`

` = 29/3 . 7/8`

` = 203/24`

b, `1,4 . 45/49 - (4/5 + 2/3) : 2 1/5`

` = 7/5 . 45/49 - (12/15 + 10/15) : 11/5`

` = 9/7 - 22/15 : 11/5`

` = 9/7 - 2/3`

` = 27/21 - 14/21`

` = 13/21`

c, `1 3/8 + 1/8 : (0,75 - 1/2) - 25% . 1/2`

`= 11/8 + 1/8 : (3/4 - 1/2) - 1/4 . 1/2`

`= 11/8 + 1/8 : 1/4           - 1/8`

`= 11/8 + 4/8 - 1/8`

`= 14/8 = 7/4`

d, `(142/24 + 41/4 - 54/12 + 63/54). (-1/2)^2`

` = ( 71/12 + 124/12 - 54/12 + 14/12) . 1/4`

` = 77/6 . 1/4`

` = 77/24`

Bài 2: Tính hợp lý

a, `(6 4/9 + 3 7/11) - 4 4/9`

` = 6 4/9 + 3 7/11 - 4 4/9`

` = (6 4/9 - 4 4/9) + 3 7/11`

` = 2 + 3 7/11`

` = 5 7/11 = 62/11`

b, `11 3/13 - (2 4/7 + 5 3/13)`

` = 11 3/13 - 2 4/7 - 5 3/13`

` = (11 3/13 - 5 3/13) - 2 4/7`

` = 6 - 2 4/7`

` = 3 3/7 = 24/7`

c, `6/25 . 7/3 + 19/25 . 7/3`

` = 7/3 . (6/25 + 19/25)`

` = 7/3 . 1 = 7/3`

d, `(1/4 + -5/13) + (2/11 + -8/13 + 3/4)`

` = 1/4 - 5/13 + 2/11 - 8/13 + 3/4`

` = (1/4 + 3/4) - (5/13 + 8/13) + 2/11`

` = 1 - 1 + 2/11`

` = 2/11`

e, `5/7 . 5/11 + 5/7 . 2/11 - 5/7 . 14/11`

` = 5/7 . (5/11 + 2/11 - 14/11)`

` = 5/7 . -7/11`

` = -5/11`

f, `6/7 + 1/7 . 2/7 + 1/7 .  5/7`

` = 6/7 + 1/7 . (2/7 + 5/7)`

` = 6/7 + 1/7 . 1`

` = 6/7 + 1/7`

` = 7/7 = 1`