Classifying Ratios Using a Decision Tree

This lesson teaches how to classify ratios using a decision tree. It covers part-to-part, part-to-total ratios, and rates, highlighting common mistakes students make when confusing these types. The lesson provides a decision tree method to identify the type of ratio by asking if the units are the same type and if one unit is part of the other. Examples are given to illustrate each type: a rate (3 blocks every 2 minutes), a part-to-part ratio (3 boys for every 2 girls), and a part-to-total ratio (3 boys for every 5 students).

What is a common mistake students make when dealing with part-to-part and part-to-total ratios?

• Adding extra items to the total

• Confusing the total number of items

• Using the wrong units

• Ignoring the ratio altogether

What is the first question you should ask to classify a ratio using a decision tree?

• How many items are in the ratio?

• Are the units in the ratio the same type?

• Is the ratio a rate?

• Is the ratio a part-to-total?

If the units in a ratio are not the same type, what is this ratio called?

• A fraction

• A part-to-part ratio

• A part-to-total ratio

• A rate

In the example '3 boys for every 2 girls', what type of ratio is this?

• A part-to-part ratio

• A rate

• A part-to-total ratio

• A fraction

In the example '3 boys for every 5 students', why is this considered a part-to-total ratio?

• Because boys are part of the total group of students

• Because boys and students are different types

• Because it involves time

• Because the numbers are different