a : 5 = 12 rest 0
a = 12 × 5 + 0
a = 60 + 0
a = 60
b : 5 = 12 rest 1
b = 12 × 5 + 1
b = 60 + 1
b = 61
c : 5 = 12 rest 2
c = 12 × 5 + 2
c = 60 + 2
c = 62
d : 5 = 12 rest 3
d = 12 × 5 + 3
d = 60 + 3
d = 63
e : 5 = 12 rest 4
e = 12 × 5 + 4
e = 60 + 4
e = 64