Estimating that we start off on the middle line, we could solve this by simply looking at a number line. Moving 9 yards ahead would put us at 9. But moving back 22 would place us at a negative number. An easy way of doing this is subtracting 9 from 22:
22 - 9 = 13
But, we already know that since the answer is to the left of zero, it will be a negative number. So we flip the sign to get -13 yards.
