2.193. Выполните действие: а) 1/5 + 1/7; б) 1/3 + 2/7; в) 3/5 + 5/6; г) 8/9 − 2/5; д) 5/12 + 1/6; е) 3/5 − 1/15; ж) 19/21 − 11/15; з) 5/12 + 10/63; и) 11/21 + 2/26; к) 5/21 − 7/60.

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Accepted Answer

а) \(\frac{1}{5}+\frac{1}{7}=\frac{7}{35}+\frac{5}{35}=\frac{12}{35}\).
б) \(\frac{1}{3}+\frac{2}{7}=\frac{7}{21}+\frac{6}{21}=\frac{13}{21}\).
в) \(\frac{3}{5}+\frac{5}{6}=\frac{18}{30}+\frac{25}{30}=\frac{43}{30}=1\frac{13}{30}\).
г) \(\frac{8}{9}-\frac{2}{5}=\frac{40}{45}-\frac{18}{45}=\frac{22}{45}\).
д) \(\frac{5}{12}+\frac{1}{6}=\frac{5}{12}+\frac{2}{12}=\frac{7}{12}\).
е) \(\frac{3}{5}-\frac{1}{15}=\frac{9}{15}-\frac{1}{15}=\frac{8}{15}\).
ж) \(\frac{19}{21}-\frac{11}{15}=\frac{95}{105}-\frac{77}{105}=\frac{18}{105}=\frac{6}{35}\).
з) \(\frac{5}{12}+\frac{10}{63}=\frac{105}{252}+\frac{40}{252}=\frac{145}{252}\).
и) \(\frac{11}{21}+\frac{2}{26}=\frac{11}{21}+\frac{1}{13}=\frac{143}{273}+\frac{21}{273}=\frac{164}{273}\).
к) \(\frac{5}{21}-\frac{7}{60}=\frac{100}{420}-\frac{49}{420}=\frac{51}{420}=\frac{17}{140}\).

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