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Ответ:
а) 3 \(\frac{3}{4}\) + 2 \(\frac{4}{7}\) = \(\frac{15}{4}\) + \(\frac{18}{7}\) = \(\frac{15*7}{4*7}\) + \(\frac{18*4}{7*4}\) = \(\frac{105}{28}\) + \(\frac{72}{28}\) = \(\frac{177}{28}\) = 6 \(\frac{9}{28}\)
б) 2 \(\frac{5}{9}\) - 1 \(\frac{1}{6}\) = \(\frac{23}{9}\) - \(\frac{7}{6}\) = \(\frac{23*2}{9*2}\) - \(\frac{7*3}{6*3}\) = \(\frac{46}{18}\) - \(\frac{21}{18}\) = \(\frac{25}{18}\) = 1 \(\frac{7}{18}\)
в) 7 \(\frac{11}{15}\) - \(3 \frac{9}{20} + 1 \frac{1}{30}\) = 7 \(\frac{11}{15}\) - \(\frac{69}{20} + \frac{31}{30}\) = 7 \(\frac{11}{15}\) - \(\frac{69*3}{20*3} + \frac{31*2}{30*2}\) = 7 \(\frac{11}{15}\) - \(\frac{207}{60} + \frac{62}{60}\) = 7 \(\frac{11}{15}\) - \(\frac{269}{60}\) = \(\frac{116}{15}\) - \(\frac{269}{60}\) = \(\frac{116*4}{15*4}\) - \(\frac{269}{60}\) = \(\frac{464}{60}\) - \(\frac{269}{60}\) = \(\frac{195}{60}\) = \(\frac{13}{4}\) = 3 \(\frac{1}{4}\)
Ответы:
а) 6 \(\frac{9}{28}\)
б) 1 \(\frac{7}{18}\)
в) 3 \(\frac{1}{4}\)
б) 2 \(\frac{5}{9}\) - 1 \(\frac{1}{6}\) = \(\frac{23}{9}\) - \(\frac{7}{6}\) = \(\frac{23*2}{9*2}\) - \(\frac{7*3}{6*3}\) = \(\frac{46}{18}\) - \(\frac{21}{18}\) = \(\frac{25}{18}\) = 1 \(\frac{7}{18}\)
в) 7 \(\frac{11}{15}\) - \(3 \frac{9}{20} + 1 \frac{1}{30}\) = 7 \(\frac{11}{15}\) - \(\frac{69}{20} + \frac{31}{30}\) = 7 \(\frac{11}{15}\) - \(\frac{69*3}{20*3} + \frac{31*2}{30*2}\) = 7 \(\frac{11}{15}\) - \(\frac{207}{60} + \frac{62}{60}\) = 7 \(\frac{11}{15}\) - \(\frac{269}{60}\) = \(\frac{116}{15}\) - \(\frac{269}{60}\) = \(\frac{116*4}{15*4}\) - \(\frac{269}{60}\) = \(\frac{464}{60}\) - \(\frac{269}{60}\) = \(\frac{195}{60}\) = \(\frac{13}{4}\) = 3 \(\frac{1}{4}\)
Ответы:
а) 6 \(\frac{9}{28}\)
б) 1 \(\frac{7}{18}\)
в) 3 \(\frac{1}{4}\)
