Контрольные задания
Вопрос:Фото задания: Вычислите выражения: 1) 3/7 + 16/28 и 2/75 + 71/450; 2) 1/6 + 5/18 и 4/7 − 16/28; 3) 5/7 + 3/14 и 4/6 − 5/18; 4) 7/15 + 3/5 и…Фото задания

Ответ:

Приводим дроби к общему знаменателю, выполняем действие и сокращаем результат.

№Левая колонкаПравая колонка
1\(\frac{3}{7}+\frac{16}{28}=\frac{3}{7}+\frac{4}{7}=1\)\(\frac{2}{75}+\frac{71}{450}=\frac{12}{450}+\frac{71}{450}=\frac{83}{450}\)
2\(\frac{1}{6}+\frac{5}{18}=\frac{3}{18}+\frac{5}{18}=\frac{8}{18}=\frac{4}{9}\)\(\frac{4}{7}-\frac{16}{28}=\frac{4}{7}-\frac{4}{7}=0\)
3\(\frac{5}{7}+\frac{3}{14}=\frac{10}{14}+\frac{3}{14}=\frac{13}{14}\)\(\frac{4}{6}-\frac{5}{18}=\frac{12}{18}-\frac{5}{18}=\frac{7}{18}\)
4\(\frac{7}{15}+\frac{3}{5}=\frac{7}{15}+\frac{9}{15}=\frac{16}{15}=1\frac{1}{15}\)\(\frac{2}{7}-\frac{3}{14}=\frac{4}{14}-\frac{3}{14}=\frac{1}{14}\)
5\(\frac{7}{15}+\frac{1}{3}=\frac{7}{15}+\frac{5}{15}=\frac{12}{15}=\frac{4}{5}\)\(\frac{7}{15}-\frac{1}{5}=\frac{7}{15}-\frac{3}{15}=\frac{4}{15}\)
6\(\frac{2}{30}+\frac{3}{5}=\frac{1}{15}+\frac{9}{15}=\frac{10}{15}=\frac{2}{3}\)\(\frac{10}{15}-\frac{2}{3}=\frac{2}{3}-\frac{2}{3}=0\)
7\(\frac{2}{7}+\frac{4}{21}=\frac{6}{21}+\frac{4}{21}=\frac{10}{21}\)\(\frac{22}{9}-\frac{7}{3}=\frac{22}{9}-\frac{21}{9}=\frac{1}{9}\)
8\(\frac{3}{5}+\frac{11}{20}=\frac{12}{20}+\frac{11}{20}=\frac{23}{20}=1\frac{3}{20}\)\(\frac{4}{7}-\frac{4}{21}=\frac{12}{21}-\frac{4}{21}=\frac{8}{21}\)
9\(\frac{1}{5}+\frac{8}{15}=\frac{3}{15}+\frac{8}{15}=\frac{11}{15}\)\(\frac{3}{5}-\frac{11}{20}=\frac{12}{20}-\frac{11}{20}=\frac{1}{20}\)
10\(\frac{12}{27}+\frac{2}{3}=\frac{4}{9}+\frac{6}{9}=\frac{10}{9}=1\frac{1}{9}\)\(\frac{3}{5}-\frac{8}{15}=\frac{9}{15}-\frac{8}{15}=\frac{1}{15}\)

Ответ: 1) 1; 83/450. 2) 4/9; 0. 3) 13/14; 7/18. 4) 1 1/15; 1/14. 5) 4/5; 4/15. 6) 2/3; 0. 7) 10/21; 1/9. 8) 1 3/20; 8/21. 9) 11/15; 1/20. 10) 1 1/9; 1/15.