Question

a) 3-1/2=

b) 3/4.(2/5+1/2)=

c) 1-3/4 sobre 2 .7/9 =

Answer 1

A) 3 - 1/2
MMC de 3 e 2 = 6
3/1/6 - 1/2/3 = 
18/6 - 3/6 = 15/6
b) 3/4. (2/5 + 1/2)
MMC de 5 e 2 = 10
3/4 . ( 2/5/2 + 1/2/5) =
3/4 . (4/10 + 5/10) =
3/4 . 9/10 =
29/40
c) 1- 3/4
----------------
     2. 7/9

MMC de 1 e 4 = 4
1/1/4 - 3/4/1
-----------------
       14/9

4/4 - 3/4
--------------
      14/9
1/4 : 14/9=
1/4 . 9/14 =
9/56 =

Answer 2

$a) \\ \\ 1 - \dfrac{1}{2}$

mmc  = 2

$\dfrac{2*3 - 1}{3} {y} => \ \ => \dfrac{5}{2}$

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$b) \\ \\  * (\dfrac{2}{5} + \dfrac{1}{2})$

No segundo termo mmc de 5, 2 = 10

$\dfrac{3}{4} * \dfrac{4 + 5}{10} \\ \\ \\ \dfrac{3}{4} * \dfrac{9}{10} \\ \\ \\ => \dfrac{27}{40}$

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$c) \\ \\ \dfrac{1 - \dfrac{3}{4} }{ 2*\dfrac{7}{9} } \\ \\ \\ \dfrac{ \dfrac{1}{4} }{ \dfrac{14}{9} }$

A fração que esta dividindo passa multiplicando e inverte a fração:


$\dfrac{1}{4} * { \dfrac{9}{14} \\ \\ \\ => \dfrac{9}{56}$