Предмет: Математика, автор: mersedecbmw606

7
657. Вычислите:
1
1 2
1) 3- +5
6 5
2
3
:11
2
; 3)
1 2
+
8 9
1) 5-
2
1
+
3 6
5
9​

Приложения:

Ответы

Автор ответа: elenamuraweva
12

Ответ:

1)

(3 \frac{1}{3}  + 5 \frac{1}{6} ) \times  \frac{2}{5}  - 2  \frac{3}{4}  \div (1 \frac{1}{2}  -  \frac{2}{5} ) =0.9  \\ 1)3 \frac{1}{3}  + 5 \frac{1}{6}  =  \frac{3 \times 3 + 1}{3}  +  \frac{6 \times 5 + 1}{6}  =   \\ \frac{10}{3}  +  \frac{31}{6}  =  \frac{10 \times 2 + 31}{6}  =  \frac{51}{6} \\ 2) \frac{51}{6}  \times  \frac{2}{5}  =  \frac{51}{15}  \\ 3)1 \frac{1}{2}  -  \frac{2}{5}  =  \frac{2 \times 1 + 1}{2}  -  \frac{2}{5}  =  \frac{3}{2}  -  \frac{2}{5}  =   \\ \frac{3 \times 5 - 2 \times 2}{10}  =  \frac{15 - 4}{10}  =  \frac{11}{10}  \\ 4)2 \frac{3}{4}  \div  \frac{11}{10}  =  \frac{4 \times 2 + 3}{4}  \div  \frac{11}{10}  =  \frac{11}{4}  \div  \frac{11}{10}  =  \\  \frac{11}{4}  \times  \frac{10}{11}  =  \frac{5}{2}  \\ 5) \frac{51}{15}  -  \frac{5}{2}  =  \frac{51 \times 2 - 5 \times 15}{30}  =  \frac{102 - 75}{30}  =  \\  \frac{27}{30}  =  \frac{9}{10}  = 0.9

2)

( \frac{1}{8}  +  \frac{2}{9}  -  \frac{1}{4} ) \times 5 \frac{1}{7}  \div ( \frac{7}{9}  -  \frac{2}{3}  +  \frac{1}{6} ) = 1 \frac{4}{5}  \\ 1) \frac{1}{8}  +  \frac{2}{9}  =  \frac{1 \times 9 + 2 \times 8}{72}  =  \frac{9 + 16}{72}  =  \frac{25}{72}  \\ 2) \frac{25}{72}  -  \frac{1}{4}  =  \frac{25 - 1 \times 18}{72}  =  \frac{25 - 18}{72}  = \frac{7}{72}   \\ 3) \frac{7}{72}  \times 5 \frac{1}{7}  =  \frac{7}{72}  \times  \frac{7  \times 5 + 1}{7}  =  \frac{7}{72}  \times  \frac{36}{7}  =  \frac{1}{2}  \\ 4) \frac{7}{9}  -  \frac{2}{3}  =  \frac{7 - 2 \times 3}{9}  =  \frac{7 - 6}{9}  =  \frac{1}{9}  \\ 5) \frac{1}{9}  +  \frac{1}{6}  =  \frac{1 \times 2 + 1 \times 3}{18}   = \frac{5}{18} \\ 6) \frac{1}{2}  \div  \frac{5}{18}  =  \frac{1}{2}  \times  \frac{18}{5}  =  \frac{9}{5}  = 1 \frac{4}{5}

Похожие вопросы
Предмет: Математика, автор: Аноним