The number with the least value is p-n when n > p, and the number with the greatest value is n+p.
Let's analyze the three expressions:
n-p: This expression represents the difference between n and p. Since n and p are plotted on the number line, n-p will always be a negative number, indicating that it lies to the left of both n and p.
n+p: This expression represents the sum of n and p. Since n and p are plotted on the number line, n+p will always be a positive number, indicating that it lies to the right of both n and p.
p-n: This expression represents the difference between p and n. Since n and p are plotted on the number line, p-n will be negative when n > p and positive when n < p.
Therefore, the number with the least value is p-n when n > p, and the number with the greatest value is n+p.