Răspuns :
45 + a = 60
a = 60 - 45
a = 15
70 - b = 35
b = 70 - 35
b = 35
c - 36 = 56
c = 56 +36
c = 92
d + 21 = 50
d = 50 - 21
d = 29
a = 60 - 45
a = 15
70 - b = 35
b = 70 - 35
b = 35
c - 36 = 56
c = 56 +36
c = 92
d + 21 = 50
d = 50 - 21
d = 29