📊Math G3 L6.8 🤔Explore A - Denominator Comparison

For this lesson you will use the Cuisenaire Rods , colored pencils or markers, math journals, and Denominator Comparison Sheet found in the lesson materials.

Cuisenaire Rods App Links to an external site.  (click link)

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Part 1

Use the Cuisenaire Rods.

a)

Model $\frac{1}{4}\:and\:\frac{3}{4}$side by side.

Which rods did you use to model these fractions?

How big is the whole?

• A length equivalent to four one-fourths

How do you know your pieces show fourths?

• It takes four of these same pieces to make the whole.

How many pieces did you use to model $\frac{1}{4}$?

• one

How many pieces did you use to model $\frac{3}{4}$?

• three

Which fraction is larger?

• $\frac{3}{4}$

How do you know?

• It takes 3 one-fourth pieces to make, it takes more pieces to make $\frac{3}{4}$.

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b)

Let's record this on the Denominator Comparison sheet.

Label the fourths on both number lines for number 1. 

Use your one-fourth size rod to measure.

Example:  Brown rod used as the whole, red as the one-fourth piece.

c)

What is the whole for each fraction?

• Both fractions refer to the same whole. (Similarity)

What is the unit fraction for each fraction?

• Both have a unit fraction of one-fourth. (Similarity)

What is the denominator of each fraction?

• Both have a denominator of 4. (Similarity)

How are they different?

• $\frac{1}{4}$ has one piece while $\frac{3}{4}$has 3 pieces
• $\frac{3}{4}$is more than $\frac{1}{4}$

If you used a different rod (not brown) as the whole, are these similarities and differences still true?

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Part 2

On your Denominator Recording Sheet, let's compare other fractions.

2) $\frac{2}{6}$ and $\frac{4}{6}$

3) $\frac{3}{3}$and $\frac{4}{3}$

4) $\frac{7}{8}$and $\frac{5}{8}$

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Part 3

Look at your rule for comparing fractions with like denominators.  

Do these models follow the rule?

Part 4