21 - 16.75 is 4.25. Do the problem on a calculator and you'll get it.
It's undefined, but I think you spelled it wrong.
Question: What is a verbal expression for w-24
Answer: What is a 24 less than a number <em>w.</em>
Explanation: It would be (What is a 24 less than a number <em>w.</em>), because less than means subtract and you will write it the opposite of how you say it.
Hope It Helps!!
