Вычисли дроби из первого и второго варианта

Вариант 1. 1. a) $\frac{3}{8} + \frac{1}{8} = \frac{3+1}{8} = \frac{4}{8} = \frac{1}{2}$ б) $2 + \frac{2}{3} + \frac{1}{12} = 2 + \frac{2*4}{3*4} + \frac{1}{12} = 2 + \frac{8}{12} + \frac{1}{12} = 2 + \frac{9}{12} = 2 + \frac{3}{4} = 2\frac{3}{4}$ в) $\frac{2}{3} + \frac{1}{4} = \frac{2*4}{3*4} + \frac{1*3}{4*3} = \frac{8}{12} + \frac{3}{12} = \frac{11}{12}$ г) $\frac{5}{6} + \frac{5}{9} = \frac{5*3}{6*3} + \frac{5*2}{9*2} = \frac{15}{18} + \frac{10}{18} = \frac{25}{18} = 1\frac{7}{18}$ д) $\frac{1}{10} + \frac{3}{100} = \frac{1*10}{10*10} + \frac{3}{100} = \frac{10}{100} + \frac{3}{100} = \frac{13}{100}$ е) $\frac{3}{20} + \frac{7}{30} = \frac{3*3}{20*3} + \frac{7*2}{30*2} = \frac{9}{60} + \frac{14}{60} = \frac{23}{60}$ 2. a) $\frac{2}{7} + \frac{6}{7} + \frac{12}{7} = \frac{2+6+12}{7} = \frac{20}{7} = 2\frac{6}{7}$ б) $\frac{1}{3} + \frac{1}{2} + \frac{5}{6} = \frac{1*2}{3*2} + \frac{1*3}{2*3} + \frac{5}{6} = \frac{2}{6} + \frac{3}{6} + \frac{5}{6} = \frac{10}{6} = \frac{5}{3} = 1\frac{2}{3}$ Вариант 2. 1. a) $\frac{7}{10} + \frac{8}{10} = \frac{7+8}{10} = \frac{15}{10} = \frac{3}{2} = 1\frac{1}{2}$ б) $\frac{4}{5} + \frac{9}{10} = \frac{4*2}{5*2} + \frac{9}{10} = \frac{8}{10} + \frac{9}{10} = \frac{17}{10} = 1\frac{7}{10}$ в) $\frac{1}{2} + \frac{2}{5} = \frac{1*5}{2*5} + \frac{2*2}{5*2} = \frac{5}{10} + \frac{4}{10} = \frac{9}{10}$ г) $\frac{5}{8} + \frac{7}{10} = \frac{5*5}{8*5} + \frac{7*4}{10*4} = \frac{25}{40} + \frac{28}{40} = \frac{53}{40} = 1\frac{13}{40}$ д) $\frac{3}{10} + \frac{1}{100} = \frac{3*10}{10*10} + \frac{1}{100} = \frac{30}{100} + \frac{1}{100} = \frac{31}{100}$ е) $\frac{1}{30} + \frac{3}{40} = \frac{1*4}{30*4} + \frac{3*3}{40*3} = \frac{4}{120} + \frac{9}{120} = \frac{13}{120}$ 2. a) $\frac{5}{9} + \frac{8}{9} + \frac{7}{9} = \frac{5+8+7}{9} = \frac{20}{9} = 2\frac{2}{9}$ б) $\frac{1}{4} + \frac{1}{2} + \frac{7}{8} = \frac{1*2}{4*2} + \frac{1*4}{2*4} + \frac{7}{8} = \frac{2}{8} + \frac{4}{8} + \frac{7}{8} = \frac{13}{8} = 1\frac{5}{8}$