This problem can be solved by pre-school children....

Вопрос: 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; 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; 5531 = 0;
3333 = 0; 2581 = ?


Ответ:
2.

Пояснение: шаблон решения - число кружков в каждой серии представленных чисел.