$frac{1}{27} + (frac{7}{9} - frac{2}{3} )$ Найти с НОК.
$42- 9frac{3}{4} - (11frac{7}{12} + 2frac{5}{18})$ Найти с НОК.
Привести дроби к общему знаменателю.
$frac{8}{11}$ и $frac{5}{8}$

$frac{7}{35}$ и $frac{61}{63}$

Ответ

Автор - fanta2310

Ответ:

Пошаговое объяснение:

1/27 + (7/9 - 2/3) = 4/27

1) 7/9 - 2/3 = $frac{7 * 1}{9 * 1}-frac{2 * 3}{3 * 3}=$ = 7/9 - 6/9 = 1/9

9 = 3 * 3 * 1

3 = 3 * 1

НОК (9 и 3) = 3 * 3 * 1 = 9

9 : 9 = 1

9 : 3 = 3

2) 1/27 + 1/9 = $frac{1 * 1}{27 * 1}+frac{1 * 3}{9 * 3}$ =1/27 + 3/27 = 4/27

27 = 3 * 3 * 3 * 1

9 = 3 * 3 * 1

НОК (27 и 9) = 3 * 3 * 3 * 1 = 27

27 : 27 = 1

27 : 9 = 3

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42 - 9 3/4 - (11 7/12 + 2 5/18) = 18 7/18

1) 11 7/12 + 2 5/18 = $11frac{7*3}{12*3} + 2frac{5 * 2}{18*2}$ = 11 21/36 + 2 10/36 = (11 + 2) + (21/36 + 10/36) = 13 31/36

12 = 2 * 2 * 3 * 1

18 = 2 * 3 * 3 * 1

НОК (12 и 18) = 2 * 2 * 3 * 3 * 1 = 36

36 : 12 = 3

36 : 18 = 2

2) 42 - 9 3/4 = 41 4/4 - 9 3/4 = 32 1/4

3) 32 1/4 - 13 31/36 = 32 9/36 - 13 31/36 = 31 45/36 - 13 31/36 = 18 14/36 = 18 7/18

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8/11 и 5/8 = 64/88 и 55/88

11 = 11 * 1

8 = 2 * 2 * 2 * 1

НОК (11 и 8) = 2 * 2 * 2 * 11 * 1 = 88

88 : 11 = 8

88 : 8 = 11

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7/35 и 61/63 = 35/315 и 305/315

35 = 5 * 7 * 1

63 = 3 * 3 * 7 * 1

НОК (35 и 63) = 5 * 7 * 3 * 3 * 1 = 315

315 : 35 = 9

315 : 63 = 5