a : 18 = x rest 3 ==> a = 18x + 3
a : 20 =y rest 3 ==> a = 20y + 3
a : 32 = z rest 3 ==> a = 32z + 3
18 = 2 × 3^2
20 = 2^2 × 5
32 = 2^5
-----------------
2^5 × 3^2 × 5 = 32×9×5 = 1 440
a = 1 440 + 3 = 1 443 (numarul)
1 443 : 18 = 80 rest 3
1 443 : 20 = 72 rest 3
1 443 : 32 = 45 rest 3