Помиогите математика. (╯︵╰,) номер 542,544. П
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542.

3 1\15+2 7/25=3 10/150+2 42/150=5 52/150=5 26/75

2 7/10+9 2/15=2 21/30+9 4/30=11 25/30=11 5/6

1 3/4+8 4/25= 1 75/100+8 16/100=9 91/100

19 5/18+6 1/12=19 10/36+6 3/36=25 13/36

11 7/12+3 5/9=11 21/36+3 20/36=14 41/36=15 5\36

15 1/21+8 1/28=15 4/84+8 3/84=23 7/84=23 1/12

5 5\24+2 1/9=5 15/72+2 8/72=7 23/72

3 1/12+4 2/15=3 5/60+4 8/60=7 13/60

6 5/18+7 6/27=6 15/54+7 12/54=13 27/54=13 1/2

Пошаговое объяснение:

543. 3 1/8 + 7 5/12 + 5 3/8 + 1/12 = (3+7+5) + (1/8+3/8) +

+ (5/12+1/12) = 15 + 4/8 + 6/12 = 15 + 1/2 + 1/2 = 16

10 2/5 + 15 5/6 + 3 3/5 + 4 1/6 = (10+15+3+4) + (2/5+3/5) +

+ (5/6+1/6) = 32 + 5/5 + 6/6 = 32 + 1 + 1 = 34

9 7/8 + 5 2/7 + 1 1/8 + 4 5/7 = (9+5+1+4) + (7/8+1/8) +

+ (2/7+5/7) = 19 + 8/8 + 7/7 = 19 + 1 + 1 = 21

15 7/8 + 11 8/9 + 4/9 + 5/8 = (15+11) + (7/8+5/8) +

+ (8/9+4/9) = 26 + 12/8 + 12/9 = 26 + 3/2 + 4/3 =

= 26 + 1 1/2 + 1 1/3 = 28 + 1/2 + 1/3 = 28 5/6

1) 12 - 7_4/9 = 11_9/9 - 7_4/9 = 4_5/9 см   - сторона ас2) 7_7/18 - 4_5/9 = 7_7/18 - 4_10/18 = 6_25/18 - 4_10/18 = 2_15/18 = 2_5/6 см - сторона вс3) 7_4/9 - 2_5/6 = 7_8/18 - 2_15/18 = 6_26/18 - 2_15/18 = 4_11/18 см - сторона ав проверка: 4_5/9 + 2_5/6 + 4_11/18 = 4_10/18 + 2_15/18 + 4_11/18 = 10_36/18 = 12 см = 12 см   - верно