Explain simply why 45 is the correct answer to: Every morning, Carla puts 79 apples in her backpack to eat for lunch. Unfortunately, Buffy stole some of Carla's apples on the school bus, and 26 apples fell out of a hole on the bottom. So at lunchtime, Carla only had 8 apples remaining. How many apples did Buffy steal from Carla?. Explanation:
Let B be the number of apples that Buffy stole. Then 79 - B - 26 = 8. Combining constants produces 53 - B = 8. Adding B to both sides produces 52 = B + 8. Thus the number of apples stolen by Buffy is B = 53 - 8 = 45.