Найдите значение выражения а) (5/6-2/3):8/9б) 2/3:(2/5+4/15)в)10:2/5-3/10г) (1...

Найдём значение выражения:

а) ( $\frac{5}{6}$ - $\frac{2}{3}$ ): $\frac{8}{9}$ = $\frac{3}{16}$
1) $\frac{5}{6}$ - $\frac{2*2}{2*3}$ = $\frac{5}{6}$ - $\frac{4}{6}$ = $\frac{1}{6}$
2) $\frac{1}{6}$ : $\frac{8}{9}$ = $\frac{1*9}{6*8}$ = $\frac{9}{48}$ = $\frac{3*3}{3*16}$ = $\frac{3}{16}$

б) $\frac{2}{3}$ :( $\frac{2}{5}$ + $\frac{4}{15}$ ) =1
1) $\frac{2}{5}$ + $\frac{4}{15}$ = $\frac{3*2}{3*5}$ + $\frac{4}{15}$ = $\frac{6}{15}$ + $\frac{4}{15}$ = $\frac{10}{15}$ = $\frac{2}{3}$
2) $\frac{2}{3}$ : $\frac{2}{3}$ = $\frac{2*3}{3*2}$ = 1

в) 10: $\frac{2}{5}$ - $\frac{3}{10}$ = 24,7
1) 10: $\frac{2}{5}$ = $\frac{10*5}{2}$ = $\frac{50}{2}$ = 25
2) 25 - $\frac{3}{10}$ = 24 $\frac{10}{10}$ - $\frac{3}{10}$ = 24 $\frac{7}{10}$ = 24,7

г) (1 $\frac{1}{2}$ + $\frac{3}{8}$ ):3= $\frac{5}{8}$
1) 1 $\frac{1}{2}$ + $\frac{3}{8}$ = $\frac{3}{2}$ + $\frac{3}{8}$ = $\frac{4*3}{4*2}$ + $\frac{3}{8}$ = $\frac{12}{8}$ + $\frac{3}{8}$ = $\frac{15}{8}$
2) $\frac{15}{8}$ :3= $\frac{15}{8*3}$ = $\frac{15}{24}$ = $\frac{5}{8}$