The task is to generate the correct answer for a given math problem.

Example Input: Problem: a man is 28 years older than his son . in two years , his age will be twice the age of his son . the present age of the son is ?
Example Output: 26

Example Input: Problem: 33 1 / 3 % of 36 ?
Example Output: 12 number

Example Input: Problem: if the function q is defined by the formula q = 5 w / ( 4 h ( z ^ 2 ) ) , by what factor will q be multiplied if w is quadrupled , h is doubled , and z is tripled ?
Example Output:
2 / 9