(100 − 81) * 3 = 57
48 * 2 − 18 = 78
19 : 4 = 4 (ост. 3)
60 : 7 = 8 (ост. 4)
(47 + 43) : 6 = 15
810 : 9 + 63 = 153
47 : 6 = 7 (ост. 5)
55 : 9 = 6 (ост. 1)

Вычисления
(100 − 81) * ☐ = 57
19 * ☐ = 57
☐ = 57 : 19
☐ = 3
 
48 * ☐ − 18 = 78
48 * ☐ = 78 + 18
48 * ☐ = 96
☐ = 96 : 48
☐ = 2
 
19 : ☐ = 4 (ост. 3)
4 * ☐ + 3 = 19
4 * ☐ = 19 − 3
4 * ☐ = 16
☐ = 16 : 4
☐ = 4
 
60 : ☐ = 8 (ост. 4)
8 * ☐ + 4 = 60
8 * ☐ = 60 − 4
8 * ☐ = 56
☐ = 56 : 8
☐ = 7
 
(47 + 43) : ☐ = 15
90 : ☐ = 15
☐ = 90 : 15
☐ = 6
 
810 : 9 + ☐ = 153
90 + ☐ = 153
☐ = 153 − 90
☐ = 63
 
47 : ☐ = 7 (ост. 5)
7 * ☐ + 5 = 47
7 * ☐ = 47 − 5
7 * ☐ = 42
☐ = 42 : 7
☐ = 6
 
55 : ☐ = 6 (ост. 1)
6 * ☐ + 1 = 55
6 * ☐ = 55 − 1
6 * ☐ = 54
☐ = 54 : 6
☐ = 9