Bill raises the flag 15 feet above the ground. Then he lowers it 8 feet and raises it another 2 feet

Bill raises the flag 15 feet above the ground. Then he lowers it 8 feet and raises it another 2 feet. how far above the ground is the flag now?

We tally up the positives and negatives:
Raise = +15
Lower = -8
Raise = +2
Total = +15 - 8 + 2
Total = 9 feet above the ground