abc-ab-c = 486
folosim sistemul zecimal
100a+10b+c - (10a+b) - c = 486
90a+10b-10a-b + c - c = 486 de unde rezulta ca capartine multimii{0,1,2 ...9)
90a + 9b = 486
10a + b = 486 / 9 = 54 a= 5 si b= 4
abc - c = 486 + 54
numerele sunt 540, 541,542,543,544,545,546,547,548,549
