Graduate Management Admission Test (GMAT) Practice Test

What is the outcome of subtracting an odd number from another odd number?

1. Even

2. Odd

3. Positive

4. Zero

The correct answer is: Even

When you subtract one odd number from another odd number, the result is always an even number. This is due to the properties of odd numbers in mathematics. An odd number can be expressed in the form of 2n + 1, where n is an integer. So, if we consider two odd numbers, say (2n + 1) and (2m + 1), where n and m are integers, the subtraction looks like this: (2n + 1) - (2m + 1) = 2n + 1 - 2m - 1 = 2(n - m). Here, (n - m) is still an integer, and therefore, 2(n - m) is an even number since it is a multiple of 2. This demonstrates that the result of subtracting one odd number from another odd number is always an even number, making the first option the correct choice. The other choices do not represent what occurs when subtracting odd numbers. The outcome cannot be odd, positive, or zero universally since the outcome strictly adheres to being even based on the nature of odd numbers.