# Misc Solution: Pre-School Math Problem

This problem can be solved by pre-school children in 5-10 minutes, by programer - in 1 hour, by people with higher education... well, check it yourself! :)

8809=6

7111=0

2172=0

6666=4

1111=0

3213=0

7662=2

9313=1

0000=4

2222=0

3333=0

5555=0

8193=3

8096=5

7777=0

9999=4

7756=1

6855=3

9881=5

5531=0

2581=?

## Solution

I leave it to you to find the rule. But as I call me a programmer, here is my 1 hour solution:

function solution(n) { var cnt = [ 1,0,0,0,1,0,1,0,2,1]; var s = 0; while (n > 0) { s+= cnt[n % 10]; n = n / 10 | 0; } return s; } solution(2581);