Based on the example given, I'm guessing you're supposed to round to the nearest thousand, so that's what I'll do.
2. Round 5339 to 5000, multiply by 6 to get the estimate of 30,000.
3. Round $879 to $1000, multiply by 8 to get the estimate of $8000.
4. Round 3182 to 3000, multiply by 5 to get the estimate of 15,000.
5. Round 4616 to 5000, multiply by 3 to get the estimate of 15,000.
6. Round $2854 to $3000, multiply by 9 to get the estimate of $27,000.
7. Round 7500 to 8000, multiply by 2 to get the estimate of 16,000.
8. Round 948 to 1000, multiply by 7 to get the estimate of 7000.