Fractions / Comparing Units

Understanding

Students should understand the importance of recognizing the scale or size of the unit when working with fractions.

What to look for

Give students time to explore the file using different sized wholes and fractions. Encourage students to explain their reasoning for each of. their answers.

Sample Assessment

Petre had (1/3) of a 6-inch long candy bar and Sande had (1/2) of 4-inch candy bar. Who had the most candy?

Answer: Petre had 2 inches of his bar because (1/3) of 6 is 2. Sande had 2 inches of her candy bar because (1/2) of 4 is 2. So they had the same amount of candy.

The Big Idea

Without knowing what each refers to, (1/2) of one thing can be the same as, more than, or less than (1/2) of another.

What are the students doing?

Students will compare fractions from different-sized wholes.

What is the teacher doing?

Be sure students understand how the interaction with the number lines supports the mathematics. Discuss scale with students.