Section 2: Calculations
I CAN: Define principle Apply the rate of return Calculate Simple interest, compound interest and the rule of 72
Principle This is the amount of money YOU put in. If I put $100 into a savings account at 1% interest, $100 is my PRINCIPLE 1% is my APY or rate of return Always make APY a decimal. EX.01 Instructor: See flipchart
Simple Interest This is the easiest type of interest to calculate Multiply Principle X Interest Rate X years invested $100 X.01 X 2 years= $2 Instructor: See flipchart; When complete use 5.3 Simple interest worksheet
Compound Interest Compound means you will earn interest on your previously earned interest. So, if you have $100 in a savings account earning 1% for 2 years and it compounds annually, you will: Year 1: 100 X.o1= $1 = 101 Year 2: 101 X.01= 1.01 = After 2 years, you have earned $2.01 (simple interest would have earned only $2) Usually interest is compounded quarterly (4X per year), semi-annually (2X per year), or annually (1 X per year) Instructor: See flipchart; When complete use 5.4 compound interest
The Rule of 72 72/%rate of return= how many years until your money doubles. DO NOT CHANGE % TO DECIMAL If I invest $100 at 1%, I will have $200 in 72 years 72/1=72 Instructor: See flipchart; When complete use 5.5 rule of 72
CAN I? Define principle Apply the rate of return Calculate Simple interest, compound interest and the rule of 72 I can prove this by completing: 5.3: simple interest 5.4: compound interest 5.5: Rule of 72