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

Input: Consider Input: Problem: if a - b = 5 and a 2 + b 2 = 31 , find the value of ab .

Output: 3

Input: Consider Input: Problem: find the area of trapezium whose parallel sides are 20 cm and 18 cm long , and the distance between them is 10 cm ?

Output: 190 cm

Input: Consider Input: Problem: 5.511 / 10.02 =
Output: 0.55