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

Example Input: Problem: there are 7 executives , including the ceo and cfo , that are asked to form a small team of 4 members . however , the ceo and cfo may not both be assigned to the team . given this constraint , how many ways are there to form the team ?
Example Output: 25

Example Input: Problem: if the average ( arithmetic mean ) of a and b is 45 and the average of b and c is 80 , what is the value of c − a ?
Example Output: 60

Example Input: Problem: the sum of all two digit numbers divisible by 6 is
Example Output:
81