Year-end Adjusting entries
Do you use these two accounts Uncollectible Accounts and Allowance of uncollectible accounts?

Confused with numbers to use. Please help me!

Credit sales of 500,000 Uncollectible Accounts expense of 1% of credit sales
Accounts receivable 130000 and Allowance for uncollectible accounts 1600.

Please help me figure this out!

These are two different methods of estimating the amount that will be uncollectible. The problem is having you do both, and they are independent of each other. (In reality you can't do both.)

See here for some explanation of how these entries work. It's a different question (and part of my answer only relevant to that question), but it includes the general explanation of the two different methods:

https://www.askmehelpdesk.com/finance-accounting/computing-ending-balance-allowance-uncollectable-accounts-196540.html#post945610