We do not do your homework: it is set for a reason. It is there so that you think about what you have been told, and try to understand it. It is also there so that your tutor can identify areas where you are weak, and focus more attention on remedial action.
Think about the task: how many "contiguous fragments" of the input number are there?
The minimum size of a fragment is 2 (or it's not divisible by 11) and the maximum is the whole number length of 7 (or if that is not allowed then one less - 6)
Which means that all the contiguous fragments are:
12, 21, 15, 55, 59, 98,
121, 215, 155, 559, 598,
1215, 2155, 1559, 5598,
12155, 21559, 15598,
121559, 215598,
1215598
They are easy to work out with a pair of nested loops.
Then all you have to do is check each fragment for divisibility, and that's trivial: the modulus operator "%" will do that for you!
Try it yourself, you may find it is not as difficult as you think!
If you meet a specific problem, then please ask about that and we will do our best to help. But we aren't going to do it all for you!