Ratios and Percentages

Unit Review Sheet

Facts and Definitions

Lesson 1: Introduction to Ratios

• A ratio shows how one value compares to another value.
• Ratios can be written in words ("3 to 4"), with a colon (3:4), or as a fraction (3/4).
• Equivalent ratios are two ratios that represent the same relationship between quantities, similar to equivalent fractions.

Lesson 2: Describing Ratios in Words and Pictures

• A part-to-whole ratio shows the relationship between a part of a group to the whole group. (5 bananas to 15 pieces of fruit or 5:15)
• A part-to-part ratio shows the relationship between two parts of a group. (5 bananas to 8 apples or 5:8)
• A whole-to-part ratio shows relationship between the whole group and one of its parts. (15 pieces of fruit to 8 apples or 15:8)

Lesson 3: Equivalent Ratios

• A tape diagram is a visual tool that uses equal-sized rectangles to represent the parts of a ratio.
• A double number line diagram is a visual tool that uses two parallel number lines to show equivalent ratios.
• Tables and graphs are useful tools for finding multiple equivalent ratios.

Lesson 4: Unit Rates

• A rate is a ratio that expresses how long it takes to do something.
• A unit rate is a rate that shows the amount of one thing per a single unit of another thing.
• Unit price (or unit cost) is the cost of a single unit of something.

Lesson 5: Percentages

• A percentage is a part-to-whole ratio in which the second number (the whole) is 100.
• Use the term "percent" or the % symbol when describing a specific number, such as "Ten percent (or 10%) of the cars sold were blue." Use the term "percentage" in general situations, such as "The man earned a percentage of each car sale."
• Fractions, decimals, and percents all represent numbers that are a part of a whole, and they can be converted from one form to the others without changing the value of the numbers.

Lesson 6: Percentage Problems

• A percentage represents a part-to-whole ratio.
• Many percentage problems can be solve using equivalent ratios.

Lesson 7: Unit Conversions

• Unit conversion is the process of converting a number expressed in one unit to an equivalent number expressed in another unit.
• Unit conversions can be written as part-to-whole ratios or whole-to-part ratios.

Lesson 8: Unit 3 Test

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Final Project: What's the Best Buy?

• The term "best buy" refers to the product that has the lowest unit price compared to other products of similar size and quality.