a) 8 = 2³
20 = 2² x 5
cmmdc[8,20] = 2² = 4
b) 12 = 2² x 3
18 = 3² x 2
cmmdc[12,18] = 2 x 3 = 6
c) 9 = 3²
32 = 2⁵
nu exista nimic comun
d) nu exista
e) 30 = 3 x 10
75 = 3 x 5²
cmmdc[30,75] = 3
f) 72 = 2³ x 3²
144 = 2⁴ x 3²
cmmdc[72,144] = 2³ x 3² = 72