Подставим вместо неизвестного числа х и решим уравнение.
8 + x = 35 - 20
8 + x = 15
x = 15 - 8
x = 7
8 + 7 = 35 - 20
9 + x = 57 - 40
9 + x = 17
x = 17 - 9
x = 8
9 + 8 = 57 - 40
6 + x = 24 - 10
6 + x = 14
x = 14 - 6
x = 8
6 + 8 = 24 - 10
x - 8 = 36 - 30
x - 8 = 6
x = 6 + 8
x = 14
14 - 8 = 36 - 30
x - 7 = 49 - 43
x - 7 = 6
x = 6 + 7
x = 13
13 - 7 = 49 - 43
x - 5 = 18 - 9
x - 5 = 9
x = 9 + 5
x = 14
14 - 5 = 18 - 9
18 - x = 29 - 20
18 - x = 9
x = 18 - 9
x = 9
18 - 9 = 29 - 20
12 - x = 60 - 56
12 - x = 4
x = 12 - 4
x = 8
12 - 8 = 60 - 56
11 - x = 95 - 90
11 - x = 5
x = 11 - 5
x = 6
11 - 6 = 95 - 90
918/3 -9 -18 18 0 ответ 306 453905\ 5 -45 39-35 40 -40 5-5 =0 ответ 90781 217301\7 21-21 7-7 30- 28=2 к 2 сносим 1 получается 21-21=0 и ответ31043 задача 1) 72:6=12 2)12:3=43)28:4 =7
1) 23 + 17 = 40
2) 21 + 39 = 60
3) 40 + 60 = 100
4) 100 + 15 = 115