Count when last digit of minutes matches last digit of number
Egs. At 12:23 you can count any number that ends with 3
At 18:21 you can count any number that ends with 1
If all minutes match with last 2 digits of count, count +10
Eg. At 12:23, if the count ends with 23, next count will be 33
If count's last 2 digits ends with numbers above 60, subtract 60.