1. Managing your Personal Finances Unit 5 Banking Earning Simple vs
Managing your Personal Finances Unit 5 Banking Earning Simple vs. Compound Interest
Take attendance – get phonetic spelling, nicknames

2. Do Now
What are 2 reasons to put your money in a savings account? Can you give 2 reasons why a person who starts saving at a young age normally out saves someone who starts saving later in life?

3. Standard
5.3 Students will understand the difference between earning simple and compound interest and will be able to calculate long term gains from savings.

4. Goals of the day:
I can:
understand the differences between earning simple and compound interest
calculate the earnings from simple and compound interest
understand the Rule of 72 (and calculate how long it will take to double my money using the Rule)

5. Simple Interest
SIMPLE INTEREST Since this section involves what can happen to your money, it should be of INTEREST to you!

6. What is Interest?
Interest is the amount you earn when you save money with a bank (in a savings account).

7. Simple Interest Formula
Simple Interest = Principal * Rate * Time
Principal – an amount of money that is lent, borrowed, saved or invested.
Rate – interest rate (expressed as a decimal 6% or .06)
Time – time period (usually in years)

8. Simple Interest Practice
Simple Interest =Principal * Rate * Time
Working Together–You saved $1,000 for 1 year at 4%.
What is the amount of interest you can expect to receive at the end of 1 year? What will be your Total Principal and Interest earned?
To calculate Interest earned:
$1, * .04 * 1 = $40.00
To calculate total amount due (Principal + Interest :
Principal ($1,000.00) + Simple Interest ($40.00) =
Total ($1,040.00)

9. Simple Interest Practice
Simple Interest =Principal * Rate * Time
Practice On your Own #1-You saved $25,000 for 25 years at 6%. What is the amount of interest you can expect to receive at the end of 25 years? What will be your Total Principal and Interest earned?
Calculate Simple Interest earned: $_____________
Show your work here:
Calculate total amount due (Principal and Interest):
$________________________

10. Simple Interest Practice
Simple Interest =Principal * Rate * Time
Practice On your Own #2 ––You saved $10,000 for 50 years at 10%. What is the amount of interest you can expect to receive at the end of 1 year? What will be your Total Principal and Interest earned?
Calculate Principal Interest earned: $_____________
Show your work here:
Calculate total amount due (Principal and Interest):
$________________________

11. Calculating Interest Handout
Please complete Part 1 of the Simple and Compound Interest Handout.

12. Calculating Interest Handout
What did you discover about how the interest rate affects the amount of interest you earn?

13. Compound Interest
Compound Interest is calculated on the initial principal and also on the accumulated interest of previous periods of a deposit or loan.
Compound Interest can be thought of as “interest on interest” and will make a deposit or a loan grow at a faster rate than Simple Interest (which is interest calculated only on the principal amount.)

14. Compound Interest (Cont.)
The rate at which compound interest accrues depends on the frequency of compounding; the higher the number of compounding periods, the greater the compound interest.
Compounding Factors:
Annual - 1
Semi-annual - 2
Quarterly - 4
Monthly - 12
Daily

15. Frequency of Compounding
As frequency of compounding
Interest Income received at end of period

16. Calculate Compound Interest
Formula: FV=PV(1+r/m)^m*t
FV- Future Value
PV-Present Value
r-rate
m-compounding factor
t- time
Compounding Factors
Annual- 1
Semi-annual- 2
Quarterly- 4
Monthly- 12
Daily- 365

17. Calculate Compound Interest
Formula: FV=PV(1+r/m)^m*t
#1 Together: Calculate Compound Interest on principal of $2, at 6% compounded annually for 10 years.
Step 1: Identify the components of the problem:
PV _______
r_________
m________
t_______________

18. Calculate Compound Interest
#1 Together: calculate Compound Interest on principal of $2, at 6% compounded annually for 10 years.
PV = $2,500
r = 6%
m = 1
t = 10
Step 2: Create the formula here:
2500(1+(.06/1))^1*10
Step 3: Plug the numbers into your calculator and solve $________________________.
Compound Interest Formula:
FV=PV(1+r/m)^m*t
Sample calculator keys:
FV=PV(1+(r/m))^(m*t)

19. Remember to Round Your Answers to Dollars!
Calculator Keys:
2500(1+(.06/1))(1*10)
4, is rounded to $4,477.12

20. Calculate Compound Interest
Compound Interest Formula:
FV=PV(1+r/m)^m*t
Sample calculator keys:
FV=PV(1+(r/m))^(m*t)
#2 Together: calculate Compound Interest on principal of $5, at 8% compounded annually for 10 years.
Step 1. Identify the components of the problem:
PV_______ r_______ m_______ t_______
Step 2: Create the formula here:
Step 3: Plug the numbers into your calculator and solve $________________________ (remember to round to $$’s)

21. Calculate Compound Interest
Compound Interest Formula:
FV=PV(1+r/m)^m*t
Sample calculator keys:
FV=PV(1+(r/m))^(m*t)
#1 On Your Own: Calculate Compound Interest on principal of $8, at 7% compounded monthly for 25 years.
Step 1. Identify the components of the problem
PV_______ r_______ m_______ t_______
Step 2: Create the formula here:
Step 3: Plug the numbers into your calculator and solve $________________________ (remember to round to $$’s)

22. Calculate Compound Interest
Compound Interest Formula:
FV=PV(1+r/m)^m*t
Sample calculator keys:
FV=PV(1+9r/m))^(m*t)
#2 On Your Own: calculate Compound Interest on principal of $8, at 7% compounded monthly for 25 years.
Step 1. Identify the components of the problem
PV_______ r_______ m_______ t_______
Step 2: Create the formula here:
Step 3: Plug the numbers into your calculator and solve $________________________ (remember to round to $$’s)

23. Calculating Interest Handout
Please complete Part 2 of the Simple and Compound Interest Handout.

24. Calculating Interest Handout
What did you discover about the around of interest you earned:
With Simple Interest compared to Compound Interest?
When you increased the frequency of compounding?
When you increased the interest rate?

25. Rule of 72
Quick way of finding out how long it will take to double your money!
Rule was first mentioned in an arithmetic book published in 1494.
Rule is:
The number 72 divided by the interest rate
The result is the number of years it will take to double your money

26. Rule of 72 (continued)
Working Together: If you save $2,000 at a 8% interest rate, how many years will it take to grow into $4,000? Rule of 72 formula: 72/Interest Rate (expressed as a number) 72/8= 9 It would take 9 years to double your money!

27. Rule of 72 (continued)
Working On Your Own: Calculate how many years will it take $1,500 to double if it grows at an interest rate of 6%? $________________________ Show your work here:

28. Rule of 72 (Now you try!)
On Your Own: Calculate the number of years it will take to double your money at Interest Rates of 12%, 9%, 4%, and 2%
12% _____
9% _____
4% _____
2% _____
What is the relationship between the rate of interest and how long it will take you to double your money?
__________________________

29. DO NOW: Laurel and Hardy Handout (Apply Compound Interest Formula)
See Handout:
Laurel and Hardy start an advertising business. They hope to do well and expect to retire someday. Laurel, who turned 25, is a saver. He puts $10,000 into his retirement account right away and intends to leave it there until he turns 60 (35 years) . Hardy, is more of a spender. He waits until he is 40 to put money away for his retirement. He realizes that he is way behind Laurel so he puts $20,000 into his retirement account and intends to keep it there until he is 60 (20 years).
Both gentlemen shopped around and found a bank that offered 8% interest compounded daily.
How much money do both of them have at age 60?

30. Goals of the day:
I can:
understand the differences between earning simple and compound interest
calculate the earnings from simple and compound interest
understand the Rule of 72

31. Exit Ticket
Please explain the picture below as it relates to Simple Interest vs. Compound Interest :