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

Example Input: Problem: the population of a city is 415600 . it increased by 25 % in the first year and decreased by 30 % in the second year . what is the population of the city at the end of second year ?
Example Output: 363650

Example Input: Problem: 5 men are equal to as many women as are equal to 8 boys . all of them earn $ 90 only . men ' s wages are ?
Example Output: $ 6

Example Input: Problem: 0.0008 ? = 0.02
Example Output:
0.0