At first,

Natural numbers from 102 to 113 are as follows:

102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113

Now,

Prime numbers among them are:

103, 107, 109, 113

Hence,

There are total 4 prime numbers out of 12 natural numbers.

Therefore,

The required fraction is