The formula for simple interest is Interest= Principle·Rate·Time
If one of these is missing, just plug in what you know. For example, if time if the principle is missing just plug in the rest. Say the interest is $264, the rate is 6% and the time is 2 years. When its plugged it, it looks like this: 264= P ·0.06·2 Now you can work it out 0.06·2 is 0.12 so 264=P 0.12. Just divide by 0.12 and your done! You can do this with any letter and just put in the info you know. I hope that this helps you! :)
