Learn on PengiBig Ideas Math, Course 2Chapter 6: Percents

Lesson 1: Percents and Decimals

In this Grade 7 lesson from Big Ideas Math Course 2, students learn how to convert between percents and decimals by moving the decimal point two places left or right, and how to express values like fractions, percents, and decimals as equivalent forms. The lesson covers writing percents such as 52% and 7% as decimals, converting decimals like 0.663 and 1.8 to percents, and applying these skills to real-life problems involving proportional comparisons. Aligned to Florida standard MAFS.7.EE.2.3, it builds fluency with percent-decimal conversions as a foundation for solving multi-step problems.

Section 1

Definition of a percent

Property

A percent is a ratio whose denominator is 100.

Examples

  • 57 out of 100 students is 57%, which is the ratio 57100\frac{57}{100}.
  • 25% means a ratio of 25100\frac{25}{100}.

Section 2

Convert a percent to a decimal

Property

To convert a percent to a decimal:

Step 1. Write the percent as a ratio with the denominator 100.

Step 2. Convert the fraction to a decimal by dividing the numerator by the denominator.

Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

Definition of a percent

Property

A percent is a ratio whose denominator is 100.

Examples

  • 57 out of 100 students is 57%, which is the ratio 57100\frac{57}{100}.
  • 25% means a ratio of 25100\frac{25}{100}.

Section 2

Convert a percent to a decimal

Property

To convert a percent to a decimal:

Step 1. Write the percent as a ratio with the denominator 100.

Step 2. Convert the fraction to a decimal by dividing the numerator by the denominator.