7. What are the two approaches used to estimate bad debts under the allowance method? 8. Which approach requires an extra step (considers the balance of the allowance account? 9. What is the direct write-off method and why isn't it permitted under GAAP? 10. What is materiality? When might companies use the direct write-off method? 11. What journal entry is required when a customer pays us with a credit card? 12. What is a factor? 13. What journal entry is required if we sell (factor) our receivables? 14. How do you calculate the interest on a promissory note? 15. What conventions are used to calculate interest? What convention does the textbook assume? 16. What does the receivables turnover ratio measure? 17. How do you calculate the average collection period