Сложение и вычитание дробей с разными знаменателями. Случай 1

Для сложения и вычитания дробей с разными знаменателями нужно привести их к общему знаменателю. Вот решения для примеров из вашего листа: 1) $\frac{3}{7} + \frac{16}{28} = \frac{12}{28} + \frac{16}{28} = \frac{28}{28} = 1$ 2) $\frac{1}{6} + \frac{5}{18} = \frac{3}{18} + \frac{5}{18} = \frac{8}{18} = \frac{4}{9}$ 3) $\frac{5}{7} + \frac{3}{14} = \frac{10}{14} + \frac{3}{14} = \frac{13}{14}$ 4) $\frac{7}{15} + \frac{3}{5} = \frac{7}{15} + \frac{9}{15} = \frac{16}{15} = 1\frac{1}{15}$ 5) $\frac{7}{15} + \frac{1}{3} = \frac{7}{15} + \frac{5}{15} = \frac{12}{15} = \frac{4}{5}$ 6) $\frac{2}{30} + \frac{3}{5} = \frac{2}{30} + \frac{18}{30} = \frac{20}{30} = \frac{2}{3}$ 7) $\frac{2}{7} + \frac{4}{21} = \frac{6}{21} + \frac{4}{21} = \frac{10}{21}$ 8) $\frac{3}{5} + \frac{11}{20} = \frac{12}{20} + \frac{11}{20} = \frac{23}{20} = 1\frac{3}{20}$ 9) $\frac{1}{5} + \frac{8}{15} = \frac{3}{15} + \frac{8}{15} = \frac{11}{15}$ 10) $\frac{12}{27} + \frac{2}{3} = \frac{4}{9} + \frac{6}{9} = \frac{10}{9} = 1\frac{1}{9}$ 11) $\frac{15}{81} + \frac{2}{9} = \frac{5}{27} + \frac{6}{27} = \frac{11}{27}$ 12) $\frac{7}{49} + \frac{1}{7} = \frac{1}{7} + \frac{1}{7} = \frac{2}{7}$ 13) $\frac{3}{2} + \frac{10}{16} = \frac{24}{16} + \frac{10}{16} = \frac{34}{16} = \frac{17}{8} = 2\frac{1}{8}$ 14) $\frac{10}{64} + \frac{1}{8} = \frac{10}{64} + \frac{8}{64} = \frac{18}{64} = \frac{9}{32}$ 15) $\frac{7}{3} + \frac{14}{27} = \frac{63}{27} + \frac{14}{27} = \frac{77}{27} = 2\frac{23}{27}$ 16) $\frac{8}{10} + \frac{1}{100} = \frac{80}{100} + \frac{1}{100} = \frac{81}{100}$ 17) $\frac{11}{100} + \frac{1}{5} = \frac{11}{100} + \frac{20}{100} = \frac{31}{100}$ 18) $\frac{112}{4} + \frac{10}{100} = 28 + \frac{1}{10} = 28\frac{1}{10}$ 19) $\frac{1}{70} + \frac{4}{210} = \frac{3}{210} + \frac{4}{210} = \frac{7}{210} = \frac{1}{30}$ 20) $\frac{14}{30} + \frac{18}{150} = \frac{70}{150} + \frac{18}{150} = \frac{88}{150} = \frac{44}{75}$ 21) $\frac{3}{75} + \frac{71}{450} = \frac{18}{450} + \frac{71}{450} = \frac{89}{450}$ 22) $\frac{4}{7} - \frac{16}{28} = \frac{16}{28} - \frac{16}{28} = 0$ 23) $\frac{4}{6} - \frac{5}{18} = \frac{12}{18} - \frac{5}{18} = \frac{7}{18}$ 24) $\frac{2}{7} - \frac{3}{14} = \frac{4}{14} - \frac{3}{14} = \frac{1}{14}$ 25) $\frac{7}{15} - \frac{1}{5} = \frac{7}{15} - \frac{3}{15} = \frac{4}{15}$ 26) $\frac{10}{15} - \frac{2}{3} = \frac{2}{3} - \frac{2}{3} = 0$ 27) $\frac{22}{9} - \frac{7}{3} = \frac{22}{9} - \frac{21}{9} = \frac{1}{9}$ 28) $\frac{4}{7} - \frac{4}{21} = \frac{12}{21} - \frac{4}{21} = \frac{8}{21}$ 29) $\frac{3}{5} - \frac{11}{20} = \frac{12}{20} - \frac{11}{20} = \frac{1}{20}$ 30) $\frac{3}{5} - \frac{8}{15} = \frac{9}{15} - \frac{8}{15} = \frac{1}{15}$ 31) $\frac{21}{27} - \frac{2}{3} = \frac{7}{9} - \frac{6}{9} = \frac{1}{9}$ 32) $\frac{63}{81} - \frac{6}{9} = \frac{7}{9} - \frac{6}{9} = \frac{1}{9}$ 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) $\frac{112}{4} - \frac{10}{100} = 28 - \frac{1}{10} = 27\frac{9}{10}$ 39) $\frac{10}{70} - \frac{4}{210} = \frac{30}{210} - \frac{4}{210} = \frac{26}{210} = \frac{13}{105}$ 40) $\frac{13}{900} - \frac{7}{450} = \frac{13}{900} - \frac{14}{900} = -\frac{1}{900}$