Question

Divisible by 3?

49,763,296

32,832,988

85,019,457

18,067,871

and how can I solve this fast?

Answer 1

The third one is divisible by 3; and you can figure that out quickly by adding up the individual numbers in each number and seeing if it is divisible by 3.
Example: 8+5+0+1+9+4+5+7 = 39 39/3 = 13
3+2+8+3+2+9+8+8 = 43 43/3 = 14 1/3

Only works like that when dividing by 3 though