Can someone tell me how to get those number?

Dec 31, 2018: Accrued interest on the note payable Date Accounts and Explanation Debit Credit 2018 Dec. 31Interest Expense 6,300 Interest Pavable 6,300 Recognized accrued interest Sep. 1, 2019: Paid the first installment on the note Date 2019 Sep. 1Interest Expense ccounts and Explanation Debit Credit 12,600 6,300 30,000 Interest Pavable Notes Pavable Cash 48,900 Paid first installment of note Dec 31, 2018: Accrued interest on the note payable Date Accounts and Explanation Debit Credit 2018 Dec. 31Interest Expense 6,300 Interest Pavable 6,300 Recognized accrued interest Sep. 1, 2019: Paid the first installment on the note Date 2019 Sep. 1Interest Expense ccounts and Explanation Debit Credit 12,600 6,300 30,000 Interest Pavable Notes Pavable Cash 48,900 Paid first installment of