Tính: a) ( $\frac{3}{8}$ + $\frac{-3}{4}$ + $\frac{7}{12}$ ) : $\frac{5}{6}$ + $\frac{1}{2}$ b) $\frac{1}{5}$ + $\frac{3}{4}$ - ( $\frac{3}{4}$ - $\frac{4}{5}$ ) + $(\frac{-1}{2})^{2}$ c) -1$\frac{13}{5}$ . 0,75 - ( $\frac{11}{20}$ + 25% ) : $\frac{7}{3}$

`a)`

`( 3/8 + {-3}/4 + 7/12 ) : 5/6 + 1/2`

`= ( -3/8 + 7/12 ). 6/5 + 1/2`

`= 5/24. 6/5 + 1/2`

`= 1/4 + 1/2`

`= 3/4`

`b)`

`1/5 + 3/4 - ( 3/4 - 4/5 ) + ( -1/2 )^2 `

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

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

`= 1 + 1/4`

`= 5/4`

`c)`

`-1 13/5. 0,75 - ( 11/20 + 25% ) : 7/3`

`= -18/5. 3/4 - ( 11/20 + 1/4 ) : 7/3`

`= -27/10 - 4/5. 3/7`

`= -27/10 - 12/35`

`= -213/70`

Đáp án:

`a, ( 3/8 + (-3)/4 + 7/12) : 5/6 +1/2`

`= 5/24 : 5/6 + 1/2`

`= 1/4 + 1/2`

`= 3/4`

$\\$

`b, 1/5 + 3/4 - ( 3/4 - 4/5) + (-1/2)^2`

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

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

`= 1 + 1/4`

`= 5/4`

$\\$

`c, -1 13/5 . 0,75 - (11/20 + 25% ) :7/3`

`= -18/5 . 3/4 - (11/20 + 1/4) : 7/3`

`= -18/5.  3/4 - 4/5 : 7/3`

`= -27/10 - 12/35`

`= -213/70`