Zahlen (1) **

8809 = 6                            5555 = 0

7111 = 0                            8193 = 3

2172 = 0                            8096 = 5

6666 = 4                            1012 = 1

1111 = 0                            7777 = 0

3213 = 0                            9999 = 4

7662 = 2                            7756 = 1

9313 = 1                            6855 = 3

0000 = 4                            9881 = 5

2222 = 0                            2581 = ???