**Vocabulary**

annual, interest rate, principal, simple interest

When you deposit money in a bank account, the bank pays you **interest** for the right to use your money for a period of time.

**Simple Interest Formula:**
*I* = p · r · *t*

**Principal ( p)** is the original amount of money deposited.

Interest is calculated based on a percent of the principal. That percent is called the **interest rate** (*r*).

**Time ( t)** is the number of years money is deposited.

**Simple interest ( I)** is interest calculated only on the principal.

**TEKS** 7(1)(D), 7(1)(F), 7(13)(E)

**Example Understanding the Simple Interest Formula**

Suppose you deposit $400 in a savings account and keep it in the bank for 6 years. The annual interest rate is 5%. Identify each value in the simple interest formula.

Digits, Grade 7, Volume 1, Homework Helper
Unit A: Number and Operations
Math Symbols
Formulas Measures
Properties

Topic 1: Operations with Rational Numbers

Unit B: Expressions, Equations, and Relationships
- 1-1: Rational Numbers, Opposites, and Absolute Value
- 1-1: TEKS Practice
- 1-2: Adding Rational Numbers
- 1-2: TEKS Practice
- 1-3: Subtracting Rational Numbers
- 1-3: TEKS Practice
- 1-4: Multiplying Rational Numbers
- 1-4: TEKS Practice
- 1-5: Dividing Rational Numbers
- 1-5: TEKS Practice
- 1-6: Operations With Rational Numbers
- 1-6: TEKS Practice
- 1-7: Additional Problem Solving
- 1-7: TEKS Practice

Topic 2: Equations & Inequalities

Unit C: Measurement and Geometry
- 2-1: Solving Simple Equations
- 2-1: TEKS Practice
- 2-2: Writing Two-Step Equations
- 2-2: TEKS Practice
- 2-3: Solving Two-Step Equations
- 2-3: TEKS Practice
- 2-4: Solving Simple Inequalities
- 2-4: TEKS Practice
- 2-5: Solving Two-Step Inequalities
- 2-5: TEKS Practice
- 2-6: Writing Problem Situations
- 2-6: TEKS Practice
- 2-7: Additional Problem Solving
- 2-7: TEKS Practice

Topic 3: Angles
Topic 4: Circles
Topic 5: Surface Area and Volume

Unit D: Proportionality
- 3-1: Measuring Angles
- 3-1: TEKS Practice
- 3-2: Adjacent Angles
- 3-2: TEKS Practice
- 3-3: Complementary Angles
- 3-3: TEKS Practice
- 3-4: Supplementary Angles
- 3-4: TEKS Practice
- 3-5: Vertical Angles
- 3-5: TEKS Practice
- 3-6: Sum of the Angles in a Triangle
- 3-6: TEKS Practice
- 3-7: Additional Problem Solving
- 3-6: TEKS Practice

- 4-1: Center, Radius, and Diameter
- 4-1: TEKS Practice
- 4-2: Circumference of a Circle
- 4-2: TEKS Practice
- 4-3: Area of a Circle
- 4-3: TEKS Practice
- 4-4: Areas of Semicircles and Quarter Circles
- 4-4: TEKS Practice
- 4-5: Area of Composite Figures
- 4-5: TEKS Practice
- 4-6: Additional Problem Solving
- 4-6: TEKS Practice

Topic 6: Ratios and Rates
Topic 7: Proportional Relationships
Topic 8: Representing Linear Relationships
Topic 9: Percents

English/Spanish Glossary
Formulas
- 9-1: The Percent Equation
- 9-1: TEKS Practice
- 9-2: Using the Percent Equation
- 9-2: TEKS Practice
- 9-3: Simple Interest
- 9-3: TEKS Practice
- 9-4: Compound Interest
- 9-4: TEKS Practice
- 9-5: Percent Increase and Decrease
- 9-5: TEKS Practice
- 9-6: Markups and Markdowns
- 9-6: TEKS Practice
- 9-7: Additional Problem Solving
- 9-7: TEKS Practice