Question 1182559
18% annual rate / 12 = 1.5% monthly rate.
if you have 1022 balance at the beginning of the month, the monthly interest charge will be .015 * 1022 = 15.33.
that interest charge is due at the end of the month.
if you miss that payment,  that charge is added to the remaining balance, and your interest payment for the next month will be (1022 + 15.33) * .015 = 15.55995.