Question

Torne elas em irredutíveis
1/4+1/5
3/5+1/3
1/8+1/4
4/7+1/3
2/5+1/10
5/6-2/3
1-3/4
3-7/8
1 1/7-4/5
2 5/6-4/3
5/7+1/6-1/21
5-1/2+5/3
3 1/5-2/3+ 2 1/3​

Answer 1

Explicação passo-a-passo:

a)

$\sf \dfrac{1}{4}+\dfrac{1}{5}=\dfrac{5+4}{20}=\red{\dfrac{9}{20}}$

b)

$\sf \dfrac{3}{5}+\dfrac{1}{3}=\dfrac{9+5}{15}=\red{\dfrac{14}{15}}$

c)

$\sf \dfrac{1}{8}+\dfrac{1}{4}=\dfrac{1+2}{8}=\red{\dfrac{3}{8}}$

d)

$\sf \dfrac{4}{7}+\dfrac{1}{3}=\dfrac{12+7}{21}=\red{\dfrac{19}{21}}$

e)

$\sf \dfrac{2}{5}+\dfrac{1}{10}=\dfrac{4+1}{10}=\dfrac{5}{10}=\red{\dfrac{1}{2}}$

f)

$\sf \dfrac{5}{6}-\dfrac{2}{3}=\dfrac{5-4}{6}=\red{\dfrac{1}{6}}$

g)

$\sf 1-\dfrac{3}{4}=\dfrac{4-3}{4}=\red{\dfrac{1}{4}}$

h)

$\sf 3-\dfrac{7}{8}=\dfrac{24-7}{8}=\red{\dfrac{17}{8}}$

i)

$\sf 1~\dfrac{1}{7}-\dfrac{4}{5}$

$\sf =\dfrac{7+1}{7}-\dfrac{4}{5}$

$\sf =\dfrac{8}{7}-\dfrac{4}{5}$

$\sf =\dfrac{40-28}{35}$

$\sf =\red{\dfrac{12}{35}}$

j)

$\sf 2~\dfrac{5}{6}-\dfrac{4}{3}$

$\sf =\dfrac{12+5}{6}-\dfrac{4}{3}$

$\sf =\dfrac{17}{6}-\dfrac{4}{3}$

$\sf =\dfrac{17-8}{6}$

$\sf =\dfrac{9}{6}$

$\sf =\red{\dfrac{3}{2}}$

k)

$\sf \dfrac{5}{7}+\dfrac{1}{6}-\dfrac{1}{21}=\dfrac{30+7-2}{42}=\dfrac{35}{42}=\red{\dfrac{5}{6}}$

l)

$\sf 5-\dfrac{1}{2}+\dfrac{5}{3}=\dfrac{30-3+10}{6}=\red{\dfrac{37}{6}}$

m)

$\sf 3~\dfrac{1}{5}-\dfrac{2}{3}+2~\dfrac{1}{3}$

$\sf =\dfrac{15+1}{5}-\dfrac{2}{3}+\dfrac{6+1}{3}$

$\sf =\dfrac{16}{5}-\dfrac{2}{3}+\dfrac{7}{3}$

$\sf =\dfrac{48-10+35}{15}$

$\sf =\red{\dfrac{73}{15}}$