Help with Journal Entries

[Bloo]

[FONT=&quot]In my Accounting Lab class, we were supposed to take record transactions in a journal and turn in an unadjusted trial balance. My balances didn't equal out, I tried asking my Professor if these two entries were correct, he told me to look at them again, without explaining what was wrong with them. Can someone tell me what I'm doing wrong here? Also, for 1) I'm not sure how to get the interest, it was obviously wrong since he told me to look at it again. Any help would be appreciated.

1) Makes mortgage payment; interest rate is 5% = $720

I have the journal entry as:

Dr Mortgage Payable 720
Dr Interest Expense 108
Cr Cash 828

[/FONT][FONT=&quot][FONT=&quot]2) Received a check from a customer written off as uncollectable last year = $75[/FONT]
[/FONT]
I had the journal entry as:

Dr Cash 75
Cr Acc Receivable 75

 

[HallsofIvy]

You realize, don't you, that the only "mathematics" involved here is:
720+ 108- 828= 0 and 75- 75= 0.

The rest is entirely accounting.