Question

помогите как это решить, пжжж​

Answer 1

Відповідь:

Покрокове пояснення:

  12 .   2/7 + 4/21 = 6/21 + 4/21 = 10/21 ;

          3/10 + 2/15 = 9/30 + 4/30 = 13/30 ;

          2/18 + 1/3 = 2/18 + 6/18 = 8/18 = 4/9 ;

          3/8 + 5/6 = 9/24 + 20/24 = 29/24 = 1 5/24 .

Answer 2

Ответ:

1)

$\frac{1}{3}$

2)

$\frac{1}{3}$

3)

$\frac{4}{9}$

4)

$\frac{29}{24}$

Пошаговое объяснение:

1)

$\frac{1}{7} + \frac{4}{21} = \frac{3 \times 1}{3 \times 7} + \frac{4}{21} = \\ = \frac{3}{21} + \frac{4}{21} = \frac{3 + 4}{21} = \\ = \frac{7}{21} = \frac{7 \times 1}{7 \times 3} = \frac{1}{3}$

2)

$\frac{2}{10} + \frac{2}{15} = \\ = \frac{3 \times 2}{3 \times 10} + \frac{2 \times 2}{2 \times 15} = \\ = \frac{6}{30} + \frac{4}{30} = \\ = \frac{6 + 4}{30} = \frac{10}{30} = \\ = \frac{10 \times 1}{10 \times 3} = \frac{1}{3}$

3)

$\frac{2}{18} + \frac{1}{3} = \frac{2}{18} + \frac{6 \times 1}{6 \times 3} = \\ = \frac{2}{18} + \frac{6}{18} = \\ = \frac{2 + 6}{18} = \frac{8}{18} = \\ = \frac{2 \times 4}{2 \times 9} = \frac{4}{9}$

4)

$\frac{3}{8} + \frac{5}{6} = \frac{3 \times 6 + 5 \times 8}{8 \times 6} = \\ = \frac{18 + 40}{48} = \frac{58}{48} = \\ = \frac{2 \times 29}{2 \times 24} = \frac{29}{24}$