Question

4 — Pratique um pouco a adição e a subtração de frações.
a) 4
7
+
2
7 b) 8
5 — 3
5 c) 3
10
+
1
4 d) 4
5 — 2

Answer 1

Explicação passo-a-passo:

a) $\sf \dfrac{4}{7}+\dfrac{2}{7}=\dfrac{4+2}{7}=\red{\dfrac{6}{7}}$

b) $\sf \dfrac{8}{5}-\dfrac{3}{5}=\dfrac{8-3}{5}=\dfrac{5}{5}=\red{1}$

c)

$\sf \dfrac{3}{10}+\dfrac{1}{4}$

$\sf mmc(10,4)=20$

$\sf \dfrac{3}{10}+\dfrac{1}{4}$

$\sf =\dfrac{3\cdot2+1\cdot5}{20}$

$\sf =\dfrac{6+5}{20}$

$\sf =\red{\dfrac{11}{20}}$

d)

$\sf \dfrac{4}{5}-2$

$\sf mmc(5,1)=5$

$\sf \dfrac{4}{5}-2$

$\sf =\dfrac{4\cdot1-2\cdot5}{5}$

$\sf =\dfrac{4-10}{5}$

$\sf =\red{\dfrac{-6}{5}}$

Answer 2

Oie, Td Bom?!

a)

= 4/7 + 2/7

= [4 + 2]/7

= 6/7

b)

= 8/5 - 3/5

= [8 - 3]/5

= 5/5

= 1

c)

= 3/10 + 1/4

= [3 . 2]/[10 . 2] + [1 . 5]/[4 . 5]

= 6/20 + 5/20

= [6 + 5]/20

= 11/20

d)

= 4/5 - 2

= 4/5 - 2/1

= 4/5 - [2 . 5]/[1 . 5]

= 4/5 - 10/5

= [4 - 10]/5

= [- 6]/5

= - 6/5

Att..Makaveli1996