Question

найдите значение выражения:
а) 7/20-(9/35-3/28)
б) (21/22-5/11) - (22/39-3/13)

Answer 1

$frac{7}{20} -( frac{9}{35} - frac{3}{28} )= frac{7}{20} -( frac{36-15}{140}) = frac{7}{20} - frac{21}{140} = frac{7}{20} - frac{3}{20} = frac{4}{20} = frac{1}{5} \ \ ( frac{21}{22} - frac{5}{11} )-( frac{22}{39} - frac{3}{13} )=( frac{21-10}{22} )-( frac{22-9}{39} )= frac{11}{22} - frac{13}{39} = frac{1}{2} - frac{1}{3} = frac{3-2}{6} = frac{1}{6}$