Question

30-Calcule.


A)1/2+3/7=


B)-2/3+4/9=


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


D)-1/3+(-1 )=

Answer 1

A)

$\frac{1}{2} + \frac{3}{7} = \frac{7 + 6}{14} = \frac{11}{14}$

mmc de 2 e 7= 14.

B)

$\frac{ - 2}{3} + \frac{4}{9} = \frac{ (- 6) + 4}{9} = \frac{ - 2}{9}$

Mmc de 3 e 9=9

C)

$\frac{5}{3} + ( \frac{ - 1}{2} ) = \frac{5}{3} - \frac{1}{2} = \frac{10 - 3}{6} = \frac{7}{6}$

mmc de 3 e 2=6

(compara o sinal, antes de calcular o mmc)

D)

$\frac{ - 1}{3} + ( - 1) = \\ \frac{ - 1}{3} - \frac{1}{1} = \\ \frac{ - 1 - 3}{3} = \\ - \frac{ - 4}{3}$