Question

(3 2/7+5/7)×7
(4-1 1/3×2)×15
9 3/8 ×2 3/7-2 5/7 ×7 3/8
3 3/4×3 3/4 + 3 3/4+3 3/4×1/4.​

Answer 1

Переводим смешанную дробь в неправильную:

1. $(3\frac{2}{7} + \frac{5}{7}) * 7 = 28$

1) $\frac{23}{7} + \frac{5}{7} = \frac{28}{7} = 4$

2) 4*7 = 28

2. $(4-1\frac{1}{3}*2)*15 =$ 20

1) $\frac{4}{3} * 2 = \frac{8}{3}$

2) $\frac{12}{3} - \frac{8}{3} = \frac{4}{3}$

3) $\frac{4}{3} * 15 = \frac{20}{1} = 20$  

3. $9\frac{3}{8} * 2\frac{3}{7} - 2\frac{5}{7} * 7\frac{3}{8} =$ 2,75

1) $\frac{75}{8} * \frac{17}{7} = \frac{1275}{56}$

2) $\frac{19}{7} * \frac{59}{8} = \frac{1121}{56}$

3) $\frac{1275}{56} - \frac{1121}{56} = \frac{154}{56} = 2,75$  

4. $3\frac{3}{4} * 3\frac{3}{4} + 3\frac{3}{4} + 3\frac{3}{4} * \frac{1}{4} =$ 18,75

1) $\frac{15}{4} * \frac{15}{4} = \frac{225}{16}$

2) $\frac{15}{4} * \frac{1}{4} = \frac{15}{16}$

3) $\frac{225}{16} + \frac{15}{4} = \frac{225}{16} + \frac{60}{16} = \frac{285}{16}$

4) $\frac{285}{16} + \frac{15}{16} = \frac{300}{16} = 18,75$