1.a Ratios

Standards Covered

M.EE.7.RP.1-3 - Use a ratio to model or describe a relationship.

Learning Goal:
• Level 2-3 – I will model and write a ratio to describe a relationship.
• Level 1 – I will match objects that represent a relationship.

Essential Questions:
• What does this ratio tell me?
• How can I model this relationship?
• How do you write a ratio that describes part-to-part or part-to-whole.

Vocabulary:
• Ratio - a way to show a relationship or compare two numbers of the same kind.
• Part-to-part - a ratio that compares a selected number of parts to a number of other parts in a whole.
• Part-to-whole - a ratio that compares a selected number of parts to the total number of parts in a whole.
• To – what is said when we state 5:8 as 5 “to” 8.
• Out of – what is said when we state 5/8 as a fraction to mean that 5 “out of” 8.
• Comparison - relations among two numbers or quantities.

A ratio is a comparison of two numbers or quantities.

Ratios that are written as part-to-whole are comparing a specific part to the whole. 
Fractions and percents are examples of part-to-whole ratios.
Fractions are written as the part being identified compared to the whole amount. 
A percent is the part identified compared to the whole (100).
Rates, a relationship between two units of measure, can be written as ratios, such as miles per hour, ounces per gallon and students per bus.
Early learning of fractions is a part of understanding ratios.
Fractions show a part of the whole.
While we identify a ¼ measuring cup as a tool, this also represents that ¼ is 1 part of a whole that has 4 parts, or the 1-cup measurement tool.
This concept of fractions can be applied to learning about a ratio.
Teaching ratio, percent and rates should be applied to real-world situations and scenarios.
A percent is a ratio that compares a number to 100. 10 percent (10%) means that there are 10 parts out of the whole of 100.
As this is calculated in a ratio, 10% may also be represented as 1 part of the whole of 10.
These concepts of ratio and percent can be presented in real-world problem-solving scenarios.