Упр.1056 ГДЗ Мерзляк Полонский 5 класс (Математика)

1) Преобразуем смешанное число в неправильную дробь:

$$9 \frac{3}{7} \cdot \frac{5}{22} = \frac{66}{7} \cdot \frac{5}{22} = \frac{3 \cdot 5}{7 \cdot 1} = \frac{15}{7} = 2 \frac{1}{7}.$$

2)

$$6 \frac{3}{8} \cdot \frac{16}{17} = \frac{51}{8} \cdot \frac{16}{17} = \frac{3 \cdot 2}{1 \cdot 1} = 6.$$

3)

$$2 \frac{1}{3} \cdot 1 \frac{1}{5} = \frac{7}{3} \cdot \frac{6}{5} = \frac{7 \cdot 2}{1 \cdot 5} = \frac{14}{5} = 2 \frac{4}{5}.$$

4)

$$19 \frac{1}{2} \cdot 1 \frac{5}{9} = \frac{39}{2} \cdot \frac{14}{9} = \frac{13 \cdot 7}{1 \cdot 3} = \frac{91}{3} = 30 \frac{1}{3}.$$

5)

$$2 \frac{1}{4} \cdot 2 \frac{2}{27} = \frac{9}{4} \cdot \frac{56}{27} = \frac{1 \cdot 14}{1 \cdot 3} = \frac{14}{3} = 4 \frac{2}{3}.$$

6)

$$2 \frac{8}{11} \cdot 5 \frac{2}{15} = \frac{30}{11} \cdot \frac{77}{15} = \frac{2 \cdot 7}{1 \cdot 1} = 14.$$

7)

$$\frac{7}{9} \cdot 1 \frac{1}{14} \cdot 5 \frac{2}{5} = \frac{7}{9} \cdot \frac{15}{14} \cdot \frac{27}{5} = \frac{1 \cdot 3 \cdot 3}{1 \cdot 2 \cdot 1} = \frac{9}{2} = 4 \frac{1}{2}.$$

8)

$$2 \frac{2}{3} \cdot 1 \frac{1}{24} \cdot 5 \frac{2}{5} = \frac{8}{3} \cdot \frac{25}{24} \cdot \frac{27}{5} = \frac{1 \cdot 5 \cdot 9}{1 \cdot 3 \cdot 1} = 15.$$

Теперь найдём проценты от числа.

1) $$1\% = \frac{1}{100}, \quad 800 \cdot \frac{1}{100} = 8.$$

2) $$1\% = \frac{1}{100}, \quad 4 \cdot \frac{1}{100} = 0{,}04.$$

3) $$12\% = \frac{12}{100}, \quad 45 \cdot \frac{12}{100} = 5{,}4.$$

4) $$15\% = \frac{15}{100}, \quad 60 \cdot \frac{15}{100} = 9.$$

5) $$84\% = \frac{84}{100}, \quad 140 \cdot \frac{84}{100} = 117{,}6.$$

6) $$120\% = \frac{120}{100}, \quad 50 \cdot \frac{120}{100} = 60.$$

Ответ

1) $$2 \frac{1}{7}$$; 2) $$6$$; 3) $$2 \frac{4}{5}$$; 4) $$30 \frac{1}{3}$$; 5) $$4 \frac{2}{3}$$; 6) $$14$$; 7) $$4 \frac{1}{2}$$; 8) $$15$$.

1) $$8$$; 2) $$0{,}04$$; 3) $$5{,}4$$; 4) $$9$$; 5) $$117{,}6$$; 6) $$60$$.