Hello. I have looked this over and over and I can't see what I did that the last 2 columns do not add up.I had to account for an owner investment of 7,000 and the fact that the company is required to make 7,500 payment on long terms notes due the following year. If anyone can spot my error that would be great. Thank you very much!

No. Account Title Debit Credit Debit Credit Debit Credit
101 Cash $7,000 7000 $0
104 Short-term investments 23,500 0 0 23,500
126 Supplies 8,200 0 0 8,200
128 Prepaid insurance 7,500 0 0 7,500
167 Equipment 45,000 0 0 45,000
168 Accumulated depreciation-Equipment $22,500 0 0 $22,500
173 Building 162,000 0 0 162,000
174 Accumulated depreciation – Building 54,000 0 0 54,000
183 Land 66,770 0 0 66,770
201 Accounts payable 17,000 17,000
203 Interest Payable 2,900 2,900
208 Rent Payable 3,500 3,500
210 Wages Payable 2,100 2,100
213 Property taxes payable 900 900
233 Unearned professional fees 7,100 7,100
251 Long-term notes payable 66,000 7000 59,000
301 E. Tamar, Capital 131,700 11000 23350 144,050
302 E. Tamar, Withdrawals 11,000 11000
401 Professional fees earned 102,000 102,000 0
406 Rent earned 15,000 15,000 0
407 Dividends earned 3,000 3,000 0
409 Interest earned 2,200 2,200 0
606 Depreciation expense - Building 11,800 0 11,800
612 Depreciation expense – Equipment 6,750 0 6,750
623 Wages expense 30,500 0 30,500
633 Interest expense 4,700 0 4,700
637 Insurance expense 8,900 0 8,900
640 Rent expense 10,900 0 10,900
652 Supplies expense 5,500 0 5,500
682 Postage expense 2,500 0 2,500
683 Property taxes expense 5,000 0 5,000
684 Repairs expense 6,200 0 6,200
688 Telephone expense 3,100 0 3,100
690 Utilities expense 3,000 0 3,000
Totals $429,900 $429,900 140200 140200 $312,970 313050

Your debit column before adjustments (very first column) adds to $429,820 instead of $429,900. I would guess that you entered one of your starting balances incorrectly.

Just as an aside, it's so easy to make that mistake. When you enter a trial balance like this, instead of entering the total for the column actually do a calc to sum it. That way you have a double check that you entered everything correctly.