In Nigeria, the price of petrol changes all the time. Likewise, in the United States, gasoline price also changes all the time. They might go down for a period of time, but then they usually rise again. One thing that stays the same is that the price is not usually a whole number. Instead, it is shown using a decimal point to describe the cost in dollars and cents. We use decimal numbers all the time, especially when dealing with money. In this tutorial, we will explore decimal numbers and how to perform operations using them.

Mathematics » Introducing Decimals » Introduction to Decimals

# Introduction to Decimals

To do 1 min read

[Attributions and Licenses]

This article has been modified from "Introduction to Decimals," by OpenStax, Prealgebra, CC BY 4.0. Download the article for free at http://cnx.org/contents/caa57dab-41c7-455e-bd6f-f443cda5519c@9.765.

This modified article is licensed under a CC BY-NC-SA 4.0 license.

### Tutorial Lessons

- Introduction to Decimals
- Naming Decimals
- Writing Decimals
- Converting Decimals to Fractions or Mixed Numbers
- Locating Decimals on the Number Line
- Ordering Decimals
- Rounding Decimals
- Key Concepts
- Adding and Subtracting Decimals
- Multiplying Decimals
- Dividing Decimals
- Using Decimals in Money Applications
- Key Concepts
- Converting Fractions to Decimals
- Ordering Decimals and Fractions
- Simplifying Expressions Using the Order of Operations
- Finding the Circumference and Area of Circles
- Key Concepts
- Determining Whether a Decimal is a Solution of an Equation
- Solving Equations with Decimals
- How to Translate to an Equation and Solve
- Key Concepts
- Introducing Averages and Probability
- Calculating the Mean of a Set of Numbers
- Finding the Median of a Set of Numbers
- Identifying the Mode of a Set of Numbers
- Using the Basic Definition of Probability
- Key Concepts
- Writing a Ratio as a Fraction
- Writing a Rate as a Fraction
- Finding Unit Rates
- Finding Unit Price
- Translating Phrases to Expressions with Fractions
- Key Concepts
- Simplifying Expressions with Square Roots
- Estimating Square Roots
- Approximating Square Roots with a Calculator
- Simplifying Variable Expressions with Square Roots
- Using Square Roots in Applications
- Key Concepts

This is a lesson from the tutorial, Introducing Decimals and you are encouraged to log in or register, so that you can track your progress.