Answer:
9,000 bottle caps.
Step-by-step explanation:
The thousands place is represented by the first 8 in this number. When we round, we round up because 880 is closer to 1,000 than to 0. This means that the number of bottle caps is closer to 9,000 than it is to 8,000. We need to gain 120 bottle caps to reach 9,000. On the other hand we need to lose 880 to reach 8,000. 120 is a smaller number than 880.