Question

7)Efetue as adiçöes e subtrações seguintes:
a)1/3+ 1/6+ 1/9 + 1/12
b)1/2 2/5+3/8
c) 14/30-6 /15
d) 16/36-21 /48

*VALE 100 PONTOS*​

Answer 1

Explicação passo-a-passo:

a) $\sf \dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{9}+\dfrac{1}{12}$

$\sf mmc(3,6,9,12)=36$

$\sf \dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{9}+\dfrac{1}{12}=\dfrac{12+6+4+3}{36}$

$\sf \dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{9}+\dfrac{1}{12}=\dfrac{25}{36}$

b) $\dfrac{1}{2}+\dfrac{2}{5}+\dfrac{3}{8}$

$\sf mmc(2,5,8)=40$

$\dfrac{1}{2}+\dfrac{2}{5}+\dfrac{3}{8}=\dfrac{20+16+15}{40}$

$\dfrac{1}{2}+\dfrac{2}{5}+\dfrac{3}{8}=\dfrac{51}{40}$

c) $\dfrac{14}{30}-\dfrac{6}{15}$

$\sf mmc(30,15)=30$

$\dfrac{14}{30}-\dfrac{6}{15}=\dfrac{14-12}{30}$

$\dfrac{14}{30}-\dfrac{6}{15}=\dfrac{2}{30}$

$\dfrac{14}{30}-\dfrac{6}{15}=\dfrac{1}{15}$

d) $\sf \dfrac{16}{36}-\dfrac{21}{48}$

$\sf mmc(36,48)=144$

$\sf \dfrac{16}{36}-\dfrac{21}{48}=\dfrac{64-63}{144}$

$\sf \dfrac{16}{36}-\dfrac{21}{48}=\dfrac{1}{144}$