This document provides instruction on calculating simple interest. It begins with the simple interest formula: I = prt, where I is interest, p is principal, r is the interest rate as a decimal, and t is time in years. The document then provides examples for students to practice calculating simple interest by finding missing variables like interest earned, interest rate, time, and principal. It concludes by having students create and trade their own simple interest problems to solve.

1. Day 9 Simple Interest Day 2.notebook February 21, 2013
OBJECTIVE: How do we find
simple interest?
Do Now
Solve the following equations.
1.) -2 x - 2 = -1 2.) -5(x - 2) = -15
3 2
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2. Day 9 Simple Interest Day 2.notebook February 21, 2013
Anticipatory Set
Compound Interest
Mortgage Payments
P[i(1 + i)]n
M=
[(1 + i)n - 1]
P = Principal
i = rate divided by 12
n = number of months
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3. Day 9 Simple Interest Day 2.notebook February 21, 2013
Simple Interest Formula: I = prt
Where I = interest
p = principal
r = interest rate as a decimal
t = time in years
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4. Day 9 Simple Interest Day 2.notebook February 21, 2013
Simple Interest
Grade: 7th
Subject: Simple Interest
Date: 2/20/13
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5. Day 9 Simple Interest Day 2.notebook February 21, 2013
1
Station 1
Find the amount of simple interest if the principal is
$15,000 with an interest rate 4% for 10 years.
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6. Day 9 Simple Interest Day 2.notebook February 21, 2013
2 Station 2
Find the interest rate if you made $420 in simple
interest from a principal of 1000 over 7 years.
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7. Day 9 Simple Interest Day 2.notebook February 21, 2013
3 Station3
Find the amount of time it would take to make $600 in simple
interest from a principal of 12,000 at a rate of 2%.
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8. Day 9 Simple Interest Day 2.notebook February 21, 2013
4
Station 4
Find the principal if your amount of simple
interest was $1000 at a rate of 7% over 4.5 years.
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9. Day 9 Simple Interest Day 2.notebook February 21, 2013
5
Station 5
Find the amount of simple interest if the principal is
$600,000 with an interest rate 4% for 9 months.
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6
Station 6
Find the interest rate if you made $5,100 in simple
interest from a principal of $20,000 over 3 years.
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11. Day 9 Simple Interest Day 2.notebook February 21, 2013
Before You Leave
1.) Create a simple interest problem similar to
the examples from today.
2.) Trade with a different group and solve their
problem.
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12. Day 9 Simple Interest Day 2.notebook February 21, 2013
Homework
Homework Sheet
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