Question

Найдите значение выражений

Answer 1

16)
$( frac{2}{3} - frac{3}{7} ) div frac{10}{21} = (frac{14}{21} - frac{9}{21} ) div frac{10}{21} = frac{5}{21} times frac{21}{10} = frac{1}{2}$
17)
$( frac{3}{4} - frac{2}{3} ) div frac{5}{6} = ( frac{9}{12} - frac{8}{12} ) div frac{5}{6} = frac{1}{12} div frac{5}{6} = frac{1}{12} times frac{6}{5} = frac{1}{2 times 5} = frac{1}{10}$
18)
$( frac{1}{7} + frac{1}{8} ) div frac{5}{28} = ( frac{8}{56} + frac{7}{56} ) div frac{5}{28} = frac{15}{56} div frac{5}{28} = frac{15}{56} times frac{28}{5} = frac{3 times 1}{2 times 1} = frac{ 3}{2}$
19)
$( frac{5}{6} - frac{3}{7} ) div frac{17}{21} = ( frac{35}{42} - frac{18}{42} ) div frac{17}{21} = frac{17}{42} div frac{17}{21} = frac{17}{42} times frac{21}{17} = frac{1}{2}$