Question

Всё действии с обыкновенными дробями 1) (5/14+17/42)*1 6/8=? 2)(5 8/9:1 17/36+1 1/4)*5/21=? 3) (2 1/4+4 5/6) :3 2/5-3/4:3/5=? 4)(3 1/4+3 5/6) :(5 3/4-3 2/3) 5) 6 4/5-2 3/4):(2 16/21+2 16/21+3 2/3)

Answer 1

$1)(\frac{5}{14}+\frac{17}{42})*1\frac{6}{8}=\frac{16}{21}\cdot\frac{14}{8}=\frac{2}{3}\cdot2=\frac{4}{3}\\\\2)(5\frac{8}{9}:1 \frac{17}{36}+1\frac{1}{4} )\cdot\frac{5}{21}=(\frac{53}{9}:\frac{53}{36}+1\frac{1}{4})\cdot\frac{5}{21}=(\frac{53}{9}\cdot\frac{36}{53}+1\frac{1}{4})\cdot\frac{5}{21}=(4+1\frac{1}{4})\cdot\frac{5}{21}=5\frac{1}{4}\cdot\frac{5}{21}=\frac{21}{4}\cdot\frac{5}{21}=\frac{1}{4}\cdot5=\frac{5}{4}$