Реши пример с дробями: 3/75 + 71/450

Конечно, давай решим эти примеры с дробями! 21) $\frac{3}{75} + \frac{71}{450} = \frac{3*6}{75*6} + \frac{71}{450} = \frac{18}{450} + \frac{71}{450} = \frac{18 + 71}{450} = \frac{89}{450}$ 22) $\frac{4}{7} - \frac{16}{28} = \frac{4*4}{7*4} - \frac{16}{28} = \frac{16}{28} - \frac{16}{28} = 0$ 23) $\frac{4}{6} - \frac{5}{18} = \frac{4*3}{6*3} - \frac{5}{18} = \frac{12}{18} - \frac{5}{18} = \frac{12 - 5}{18} = \frac{7}{18}$ 24) $\frac{2}{7} - \frac{3}{14} = \frac{2*2}{7*2} - \frac{3}{14} = \frac{4}{14} - \frac{3}{14} = \frac{4 - 3}{14} = \frac{1}{14}$ 25) $\frac{7}{15} - \frac{1}{5} = \frac{7}{15} - \frac{1*3}{5*3} = \frac{7}{15} - \frac{3}{15} = \frac{7 - 3}{15} = \frac{4}{15}$ 26) $\frac{10}{15} - \frac{2}{3} = \frac{10}{15} - \frac{2*5}{3*5} = \frac{10}{15} - \frac{10}{15} = 0$ 27) $\frac{22}{9} - \frac{7}{3} = \frac{22}{9} - \frac{7*3}{3*3} = \frac{22}{9} - \frac{21}{9} = \frac{22 - 21}{9} = \frac{1}{9}$ 28) $\frac{4}{7} - \frac{4}{21} = \frac{4*3}{7*3} - \frac{4}{21} = \frac{12}{21} - \frac{4}{21} = \frac{12 - 4}{21} = \frac{8}{21}$ 29) $\frac{3}{5} - \frac{11}{20} = \frac{3*4}{5*4} - \frac{11}{20} = \frac{12}{20} - \frac{11}{20} = \frac{12 - 11}{20} = \frac{1}{20}$ 30) $\frac{3}{5} - \frac{8}{15} = \frac{3*3}{5*3} - \frac{8}{15} = \frac{9}{15} - \frac{8}{15} = \frac{9 - 8}{15} = \frac{1}{15}$ 31) $\frac{21}{27} - \frac{2}{3} = \frac{21}{27} - \frac{2*9}{3*9} = \frac{21}{27} - \frac{18}{27} = \frac{21 - 18}{27} = \frac{3}{27} = \frac{1}{9}$ 32) $\frac{63}{81} - \frac{6}{9} = \frac{63}{81} - \frac{6*9}{9*9} = \frac{63}{81} - \frac{54}{81} = \frac{63 - 54}{81} = \frac{9}{81} = \frac{1}{9}$ 33) $\frac{48}{49} - \frac{4}{7} = \frac{48}{49} - \frac{4*7}{7*7} = \frac{48}{49} - \frac{28}{49} = \frac{48 - 28}{49} = \frac{20}{49}$ 34) $\frac{10}{64} - \frac{1}{8} = \frac{10}{64} - \frac{1*8}{8*8} = \frac{10}{64} - \frac{8}{64} = \frac{10 - 8}{64} = \frac{2}{64} = \frac{1}{32}$ 35) $\frac{7}{3} - \frac{14}{27} = \frac{7*9}{3*9} - \frac{14}{27} = \frac{63}{27} - \frac{14}{27} = \frac{63 - 14}{27} = \frac{49}{27}$ 36) $\frac{8}{10} - \frac{1}{100} = \frac{8*10}{10*10} - \frac{1}{100} = \frac{80}{100} - \frac{1}{100} = \frac{80 - 1}{100} = \frac{79}{100}$ 37) $\frac{40}{100} - \frac{1}{5} = \frac{40}{100} - \frac{1*20}{5*20} = \frac{40}{100} - \frac{20}{100} = \frac{40 - 20}{100} = \frac{20}{100} = \frac{1}{5}$ 38) $\frac{112}{4} - \frac{10}{100} = \frac{112*25}{4*25} - \frac{10}{100} = \frac{2800}{100} - \frac{10}{100} = \frac{2800 - 10}{100} = \frac{2790}{100} = 27\frac{9}{10}$ 39) $\frac{10}{70} - \frac{4}{210} = \frac{10*3}{70*3} - \frac{4}{210} = \frac{30}{210} - \frac{4}{210} = \frac{30 - 4}{210} = \frac{26}{210} = \frac{13}{105}$ 40) $\frac{13}{900} - \frac{7}{450} = \frac{13}{900} - \frac{7*2}{450*2} = \frac{13}{900} - \frac{14}{900} = \frac{13 - 14}{900} = -\frac{1}{900}$