📚Lesson

Introduce ratios and proportions

Use the Google slides presentation for definition of ratio and proportion and some practice problems.

NOTE TO TEACHER: This presentation includes multiple explanations for multiple levels of understanding. There is a solution using algebra, with cross-multiplication and an explanation of why cross-multiplication works. There is also an explanation using equivalent fractions. If you are teaching an algebra class, use the first explanation and delete the second. For a more basic math class, delete the first explanation and just use equivalent fractions.

Use ratio and proportion in real life

The end of the presentation gives a recipe for biscuits. You can delete the answer in slide 29 if you want to test their knowledge or you can leave it in for students to check themselves.

Here are three ways you can use this:

• Have students actually bake using their recipe solution.
• Have students simply answer the question (easiest)
• Select one or more incorrect answers as well as the correct answer and bake yourself. Then bring the results in and have students taste them. This takes more work from the teacher but can be pretty hilarious if you feel in a baking mood or can get a volunteer to do it.

Assessment

Assessment can be done as a group, having students answer the questions posed in the presentation or students can submit answers individually.

Related lesson

Ratios as fractions is a nine-minute video that can be used to preview this material or for re-teaching for those students who are still struggling.