Decimals

Gasoline price changes all the time. It might go down for a period of time, but then it usually rises 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 chapter, we explore decimal numbers and how to perform operations using them.

Sections

• Decimals — naming and writing decimals, converting decimals to fractions or mixed numbers, locating decimals on the number line, ordering decimals, and rounding decimals.
• Decimal Operations — adding, subtracting, multiplying, and dividing decimals, multiplying and dividing by powers of ten, and using decimals in money applications.
• Decimals and Fractions — converting fractions to decimals (including repeating decimals), ordering decimals and fractions, simplifying expressions with the order of operations, and finding the circumference and area of circles.
• Solve Equations with Decimals — determining whether a decimal is a solution of an equation, solving equations with decimals, and translating word sentences to equations.
• Averages and Probability — calculating the mean, median, and mode of a set of numbers, and using the basic definition of probability.
• Ratios and Rate — writing ratios and rates as fractions, finding unit rates and unit price, and translating phrases to expressions with fractions.
• Simplify and Use Square Roots — simplifying expressions with square roots, estimating and approximating square roots, simplifying variable expressions with square roots, and using square roots in applications.

This chapter overview is adapted from Prealgebra 2e, Chapter 5 Introduction by Lynn Marecek, MaryAnne Anthony-Smith, and Andrea Honeycutt Mathis, © OpenStax, licensed under CC BY-NC-SA 4.0. Access the original for free at openstax.org. Changes: condensed the chapter introduction and recast the chapter outline as a section list.