divizibilitatea cu 2
b=0,2,4,6,8
divizibilitatea cu 3
b=0 ⇒ a+4+0=6, 9, 12, a=2, a=5, a=8
b=2 ⇒ a+4+2=9, 12, 15, a=3, a=6, a=9 a≠0
b=4 ⇒ a+4+4=9, 12, 15, a=1, a=4, a=7
b=6 ⇒ a+4+6=12, 15, 18 a=2, a=5, a=8
b=8 ⇒ a+4+8=15, 18, 21 a=3, a =6, a=9
numerele sunt:
240, 540, 849, 342, 642, 942, 144, 444, 744, 246, 546, 846, 348, 648,948