Реши примеры на вычитание дробей: 21/27 - 2/3

31) $\frac{21}{27} - \frac{2}{3} = \frac{21}{27} - \frac{18}{27} = \frac{3}{27} = \frac{1}{9}$ 32) $\frac{63}{81} - \frac{6}{9} = \frac{63}{81} - \frac{54}{81} = \frac{9}{81} = \frac{1}{9}$ 33) $\frac{48}{49} - \frac{4}{7} = \frac{48}{49} - \frac{28}{49} = \frac{20}{49}$ 34) $\frac{10}{64} - \frac{1}{8} = \frac{10}{64} - \frac{8}{64} = \frac{2}{64} = \frac{1}{32}$ 35) $\frac{7}{3} - \frac{14}{27} = \frac{63}{27} - \frac{14}{27} = \frac{49}{27} = 1\frac{22}{27}$ 36) $\frac{8}{10} - \frac{1}{100} = \frac{80}{100} - \frac{1}{100} = \frac{79}{100}$ 37) $\frac{40}{100} - \frac{1}{5} = \frac{40}{100} - \frac{20}{100} = \frac{20}{100} = \frac{1}{5}$ 38) $\frac{112}{4} - \frac{10}{100} = \frac{2800}{100} - \frac{10}{100} = \frac{2790}{100} = 27\frac{9}{10}$ 39) $\frac{10}{70} - \frac{4}{210} = \frac{30}{210} - \frac{4}{210} = \frac{26}{210} = \frac{13}{105}$ 40) $\frac{13}{900} - \frac{7}{450} = \frac{13}{900} - \frac{14}{900} = -\frac{1}{900}$