№1. Вычислите: а) 2 1/3 + 1 1/3, 6) 4 - 2 4/7, в) 2,5 + 1 2/3, г) 1 1/4 - 1 5/6, д) 3/8 · 2 2/3, е) 3/7 : 10, ж) 8/9 : 27/9, з) 2 2/3 : 9', и) 17/25 · 2/7 : 7/5 · 2/9

1. Вычисление

1. а) 2\( \frac{1}{3} \)+1\( \frac{1}{3} \)=3\( \frac{2}{3} \)

2. б) 4 - 2\( \frac{4}{7} \)=3\( \frac{7}{7} \)-2\( \frac{4}{7} \)=1\( \frac{3}{7} \)

3. в) 2,5 + 1\( \frac{2}{3} \)=2\( \frac{1}{2} \)+1\( \frac{2}{3} \)=2\( \frac{3}{6} \)+1\( \frac{4}{6} \)=3\( \frac{7}{6} \)=4\( \frac{1}{6} \)

4. г) 1\( \frac{1}{4} \)-1\( \frac{5}{6} \)=1\( \frac{3}{12} \)-1\( \frac{10}{12} \)=-\( \frac{7}{12} \)

5. д) \( \frac{3}{8} \)· 2\( \frac{2}{3} \)= \( \frac{3}{8} \)·\( \frac{8}{3} \)=1

6. е) \( \frac{3}{7} \): 10 = \( \frac{3}{7} \)· \( \frac{1}{10} \)= \( \frac{3}{70} \)

7. ж) \( \frac{8}{9} \): \( \frac{27}{9} \)= \( \frac{8}{9} \)· \( \frac{9}{27} \)= \( \frac{8}{27} \)

8. з) 2\( \frac{2}{3} \): 3 = \( \frac{8}{3} \): 3 = \( \frac{8}{3} \)· \( \frac{1}{3} \)= \( \frac{8}{9} \)

9. и) \( \frac{17}{25} \)· \( \frac{2}{7} \): \( \frac{7}{5} \)· \( \frac{2}{9} \)= \( \frac{17}{25} \)· \( \frac{2}{7} \)· \( \frac{5}{7} \)· \( \frac{2}{9} \)= \( \frac{17·2·5·2}{25·7·7·9} \)= \( \frac{340}{7875} \)= \( \frac{68}{1575} \)