1985

What number corresponds to 1985?

0 0 0 0 - 4

1 7 5 2 - 0

1 8 7 9 - 3

2 0 6 1 - 2

3 1 4 1 - 1

4 0 9 6 - 4

7 7 7 7 - 0

9 9 7 3 - 2

1 9 8 5 - ???


SOLUTION

The numbers on the right count the total number of "holes" in the digits on the left. "1", "2", "3", "4", "5" and "7" have 0 holes in them. "0", "6" and "9" have 1 hole in them. "8" has 2 holes in it. Therefore the missing number is 2.