Question

Выполните вычитание: 1)1/3-1/9;2)10/21-1/3;3)14/15-3/5;4)17/18-1/9;5)4/9-13/45;6)1/3-7/30.

Answer 1

$displaystylefrac{1}{3} -frac{1}{9} =frac{1*3}{3*3}-frac{1}{9}=frac{3}{9}-frac{1}{9}=frac{2}{9}$

$displaystylefrac{10}{21}-frac{1}{3}=frac{10}{21}-frac{1*7}{3*7}=frac{10}{21}-frac{7}{21}=frac{3}{21}=frac{1*3}{7*3}=frac{1}{7}$

$displaystylefrac{14}{15}-frac{3}{5}=frac{14}{15}-frac{3*3}{5*3}=frac{14}{15}-frac{9}{15}=frac{5}{15}=frac{1*5}{3*5}=frac{1}{3}$

$displaystylefrac{17}{18}-frac{1}{9}=frac{17}{18}-frac{1*2}{9*2}=frac{17}{18}-frac{2}{18}=frac{15}{18}=frac{5*3}{6*3}=frac{5}{6}$

$displaystylefrac{4}{9}-frac{13}{45}=frac{4*5}{9*5}-frac{13}{45}=frac{20}{45}-frac{13}{45}=frac{7}{45}$

$displaystylefrac{1}{3}-frac{7}{30}=frac{1*10}{3*10}-frac{7}{30}=frac{10}{30}-frac{7}{30}=frac{3}{30}=frac{1*3}{1*10}=frac{1}{10}$