6. a) Use a number line to list the whole numbers between 16 and 25 What number is halfway between 16 and 25? Use the number line in part a) to help you.

The number line is drawn as shown below
Since the interval between each whole number on the number line is 1. the halfway distance would be 1/2 = 0.5
Thus, the number that is halfway between 16 and 25 lies between 20 and 21
The difference between 16 and 25 is 25 - 16 = 9
9/2 = 4.5
Thus, the number that is halfway between 16 and 25 is 16 + 4.5 = 20.5
The answer is 20.5