Suppose that J and K are on the number line. If JK=9 and J lies at 4 where could K be located?

Suppose that J and K are on the number line. If JK=9 and J lies at 4 where could K be located?

We'd need 9 spaces to the right of 4 or 9 spaces to the left of 4 to have JK be 9.

To the right:
K = 4 + 9
K = 13

K = 4 - 9
K = -5