Period:
Lesson plan for the week ending November16, 2018& November 23, 2018
Subject:
Mathematics
Grade:
11 & CAP
Duration:
80*6 minutes per session
Topic:
Consumer Arithmetic
Subtopic:
Compound Interest & Depreciation
Teachers:
Mrs. Tingling-Hamilton, Miss Smith, Mrs. Davis Brown & Mr. Rose Green
General Objectives: To help students appreciate that transactions with money are integral to
everyday life.
Specific Objectives: students should be able to
1. Explain the following term; compound interest and accumulate.
2. Apply the manual method to calculate compound interest of various investments not
exceeding 4 years.
3. Determine the difference between simple interest and compound interest after using both
techniques to solve the same problem.
4. Calculate compound interest of various investments not exceeding 4 years using the
compound interest formula.
5. Explain the following terms; depreciation, assets and deduction.
6. Apply the manual method to calculate deprecation on assets not exceeding 3 years.
7. Calculate deprecation on assets not exceeding 3 years using the depreciation formula.
8. Compare and contrast depreciation and compound interest
Resources:
1. Mathematics A Complete Course Volume 1 by Raymond Toolsie, pp 216-224
2. CXC Basic Mathematics by A. Greer & C.E. Layne pp 67-70
3. https://njaes.rutgers.edu/money/pdfs/DoE-Lesson-Plan-2-Money-Management.pdf
Previous knowledge: simple interest, approximation, percentages, currency
Instructional Strategies: questioning, problem solving, discussion
Instructional Materials: scientific calculator
Content Summary:
Compound Interest- Interest that is credited daily, monthly, quarterly, semi-annually, or annually on both
principal and previously credited interest.
A = P (1 + r/100)n
Depreciation is a reduction in the value of an asset over time, due in particular to wear and tear.
A = P (1 - r/100)n
Week 1
Procedure
The day’s objectives will be communicated to the students and will be written on the board for
students to copy in their books.
Lesson 1 Objective 1, 2, 3 &4
Revision/Introduction:
Students will be asked to recall the simple interest formula. (I=PRT/100) Teacher will record the
correct response on the board.
Students will be given a simple interest problem to solve.
$9600 invested at 8% per annum simple interest for 5 years.
𝑃∗𝑅∗𝑇
Simple Interest = 100 =
$9600∗8∗5
100
$384000
=
100
= $3840
Teacher will observe students, assist those who have problems and clear up misconceptions. The
correct answer will be written on the white board for studies to copy. Students and teacher will
discuss the types of interests. There are two types of interests: (1) simple interest and (2)
compound interest. Compound interest is the addition of interest to the principal sum of a loan or
deposit, or in other words, interest on interest. It is the result of reinvesting interest, rather than
paying it out, so that interest in the next period is then earned on the principal sum plus
previously accumulated interest. Compound interest is standard in finance and
economics. The simple annual interest rate is the interest amount per period, multiplied by the
number of periods per year.
Students will solve the following: $1400 is invested for 4years at 5% per annum. Calculate the
simple interest and the total amount. I=$280, A=$1680. A student will be chosen at random to
come to the board to complete the problem. Teacher will observe and make corrections if
necessary.
Step1: Teacher and students will engage in a discussion about the following terms; interest,
compound interest and accumulate. Students will write definitions for the above terms in their
books. Teacher will move around and supervise as students write and make correction where
necessary.
Step2:
Scenario1: Teacher will ask students whether they would lend money to a friend or sibling and,
if so, would they expect to be paid back more than they lent because their money was
unavailable for a period of time? Teacher will be aware that answers will vary but the teacher
will prompt students to respond using the key point that interest is a sum of money that is paid
for the use of someone else’s money. Financial institutions (banks and credit unions) always
charge interest when they make loans. They also pay interest when depositors put their money
in a savings account.
Teacher will demonstrate using the manual method how to calculate compound interest. Students
will ask related questions and teacher will answer and explain.
$7500 is deposited in a bank paying 14% compound interest per annum.
What is the balance after 3 years?
1st P=$7500, R=14%, T=3years
I= 14% of $7500= $1050
Total amount after the first year= $7500+ $1050= $8550
2nd I= 14% of $8550= $1197
Total amount after the second year= $8550+ $1197= $9747
3rd 14 % of $9747= $1364.58
Total amount after the third year= $9747+ $1364.58= $11111.58 or $11112
Total interest at the end of the three years=$1050+$1197+$1364.58= $3611.58 or $3612
Students will be placed in groups of six. Three questions will be written on the board. Three
persons from each group will be solving the problems using the simple interest formula while the
other three will be calculating using the compound interest manual method.
1. $1000 is deposited in a bank paying 5% per annum. What is the balance after 2 years?
=$11025
2. John invested $5000 for 4 years at 15% interest. Calculate the amount after this period.
=$8745.03
3. Keisha borrows $15000 for 3 years at 12% interest. How much will she repay after the 3
years?
=$21073.92
Each group will report their answers (which is the interest and total amount using both methods).
Teacher will record the answers on the board.
Students will examine the interest and the total amount obtained from methods. They will be
asked to tell which is better and to provide justification for their answers.
Students will also say when they would prefer interest to be compounded or simple; giving
reasons for their answers. Teacher will listen and clear misconceptions.
Possible answers: Students’ answers will vary but must include; how compound interest can
work for or against someone, the high cost of making minimum payments, and the growth of
money that is saved over time.
Step3: Teacher will write the compound interest formula on the board and explain it. Students
will make an attempt to substitute the values in the formula to ascertain the answer for the
question in step 2. Teacher will observe as students work and make corrections where necessary.
$7500 is deposited in a bank paying 14% compound interest per annum.
What is the balance after 3 years?
A= 7500(1+ 14\100)3
A= $11112
I= $3612
Assessment
Students will write a paragraph explaining which method works best and at what time (manual
and formula). Teacher will read, mark, motivate and make corrections. Students will be given
feedback on their progress.
Students will be asked to:
Do independent practice from CXC Basic Mathematics by A. Greer & C.E. Layne pp 67-70
Exercise 9.2 # 1,3,7,8
Evaluation2:
Lesson 1 Objective 5, 6, 7 &8
Week 2
Depreciation
Procedure:
The day’s objectives will be communicated to the students and will be written on the board for
students to copy in their books.
Revision/Introduction:
Teacher will give students the following problems to solve.
Decrease 20% of $6000
Ans. $4800
Decrease 15% of $8000
Ans. $6800
Students will attempt to solve the problems. Teacher will move around and supervise as students
write and make correction where necessary. The correct answers will be written on board.
Step 1: Teacher and students will engage in a discussion about the following terms; depreciation,
deduction and assets. Students will write definitions for the above terms in their books. Teacher
will move around and supervise as students write and make correction where necessary.
The following questions will be posed to students:
1. How many of you have bought a video game?
2. Have you ever traded or swapped your video game? How much did you get back,
compared to the amount you originally paid?
3. How about your parents’ car, computer, bike or machines?
Possible answers: get back less as the value of the assets decreases in value due to wear and
deterioration in general with the passing of time. (Age of assets)
Teacher will explain to students that almost everything we buy loses value over time, but
computers do so faster than most things. Teacher will ask students why computers lose value so
fast. Possible answers: Computer technology undergoes rapid change, wear and tear, usage, care,
and the age of the computer.
Step2:
Teacher will demonstrate using the manual method how to calculate compound interest. Students
will ask related questions and teacher will answer and explain.
The rate of depreciation of a motor vehicle brought for $10,000 is 30%per annum. What is its
value at the end of 2 years?
1st I= 30% of $10000= $3000
Total amount after the first year= $10000- $3000= $7000
2nd I= 30% of $7000= $2100
Total amount after the first year= $7000- $2100= $4900
Step3: Teacher will write the depreciation formula on the board and explain it. Students will
make an attempt to substitute the values in the formula to ascertain the answer for the question in
step 2. Teacher will observe as students work and make corrections where necessary.
A= $10000(1 - 30/100)2
A= $4900
Assessment:
Students will write a paragraph comparing and contrasting depreciation and compound interest.
Teacher will look for similarities between depreciation and compound interest except that with
compound interest is added to the amount from the previous year while depreciation the interest
is subtracted from the previous year.
Students will be asked to:
Do independent practice from CXC Basic Mathematics by A. Greer & C.E. Layne pp 67-70
Exercise 9.3 #1, 2, 3, 4
Evaluation2: