Answer:
The smallest value the expression could have is 1.
Explanation:
If a and b are different numbers selected from the first 25 whole numbers (1 through 25), and a is greater than b, the smallest value the expression could have is when b is the smallest possible value and a is the next smallest value.
The smallest possible value for b is 1, and a must be greater than b. Therefore, the smallest possible value for a is 2.
So, the smallest value the expression could have is 2 - 1 = 1.