CH04-01 lesson

Fraction as Sum of Unit Fractions Learning Activity

A focused Grade 4 learning session for Fraction as Sum of Unit Fractions using visual models, worked examples, strategy guidance, and a short mastery check.

15
minutes
6
lesson parts
11
practice items
Learning goal

Students will decompose a fraction into a sum of unit fractions and represent the decomposition with equations and models.

Student goal: I can write a fraction as a sum of unit fractions.

Helpful first: Equivalent Fractions
concept

Learn the Idea

Fraction as Sum of Unit Fractions means using equal parts, number lines, and clear fraction language to describe parts of a whole.

  • Identify the whole before naming a fraction.
  • Make sure each part is equal in size.
  • Use a number line or model to show where the fraction belongs.
  • Explain whether two fractions have the same size or different sizes.
visual model

See the Math

Visual Model 1

Question: Which fraction bar shows \(\frac{4}{6}\) as a sum of unit fractions?

Visual Model 1

  • A. 4 parts shaded, 6 total
  • B. 3 parts shaded, 3 total
  • C. 3 parts shaded, 4 total
  • D. 2 parts shaded, 3 total

Why it works: In the fraction bar, we have 4 shaded parts out of 6 equal parts. Each piece is a unit fraction \(\frac{1}{6}\). So we have \(\mathbf{\frac{4}{6}=\underbrace{\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}}_{4 \text{ copies}}}\).

Answer: 4 parts shaded, 6 total

worked example

Follow a Worked Example

Example 1

Question: A number line shows jumps of \(\frac{1}{3}\). Which number of jumps gets us to \(\frac{2}{3}\)?

Example 1

  • A. 1 jump
  • B. 2 jumps
  • C. 3 jumps
  • D. 6 jumps
  1. Each jump moves us forward by \(\frac{1}{3}\).
  2. To land on \(\frac{2}{3}\), we need \(\mathbf{2 \text{ jumps}}\): \(\frac{1}{3}+\frac{1}{3}=\frac{2}{3}\).

Answer: 2 jumps

Example 2

Question: Which picture shows \(\frac{3}{4}\) as a sum of unit fractions?

Example 2

  • A. 3 of 4 parts
  • B. 2 of 2 parts
  • C. 4 of 4 parts
  • D. 1 of 2 parts
  1. \(\frac{3}{4}\) shows 3 shaded parts out of 4 equal parts.
  2. Since each part is \(\frac{1}{4}\), we have \(\mathbf{\frac{3}{4}=\frac{1}{4}+\frac{1}{4}+\frac{1}{4}}\)—three unit fractions added.

Answer: 3 of 4 parts

real world

Connect It to a Real Situation

Problem 1

Question: A recipe needs \(\frac{2}{3}\) cup of flour. How can we write this as a sum of unit fractions?

  • A. \(\frac{1}{3}+\frac{1}{3}\)
  • B. \(\frac{1}{2}+\frac{1}{2}\)
  • C. \(\frac{2}{3}+\frac{1}{3}\)
  • D. \(\frac{1}{6}+\frac{1}{6}\)

Why it works: The recipe needs \(\frac{2}{3}\) cup of flour. This is 2 equal pieces, each \(\frac{1}{3}\) cup. So \(\mathbf{\frac{2}{3}=\frac{1}{3}+\frac{1}{3}}\).

Answer: \(\frac{1}{3}+\frac{1}{3}\)

strategy

Avoid Mistakes and Choose a Strategy

  • Counting unequal parts as if they were equal.
  • Forgetting that the denominator tells how many equal parts make the whole.
  • Comparing fractions without first checking the size of the whole.
  • Placing a fraction on a number line without counting equal intervals.
  • Draw the whole first, then divide it into equal parts.
  • Use number lines when the question asks about order or location.
  • Say the fraction out loud to connect numerator and denominator meanings.
  • Check whether the answer should be closer to 0, 1/2, or 1.
summary

Remember the Key Idea

Fraction as Sum of Unit Fractions becomes easier when students connect the question to a model, use clear steps, and explain why the answer fits.

GOLDEN RULE

Equal parts first, fraction name second.

Guided to independent practice

Solve before opening the answer

Use scratch paper. The explanation matters more than simply seeing whether the choice is correct.

warmup

2 questions
G4-C04-T01-Q001 About 1 min

Which expression shows \(\frac{3}{5}\) as a sum of unit fractions?

  1. A \(\frac{1}{5}+\frac{1}{5}\)
  2. B \(\frac{1}{5}+\frac{1}{5}+\frac{1}{5}\)
  3. C \(\frac{3}{5}+\frac{3}{5}+\frac{3}{5}\)
  4. D \(\frac{3}{5}\)
Check answer and explanation

Answer B: \(\frac{1}{5}+\frac{1}{5}+\frac{1}{5}\)

A unit fraction always has a numerator of \(1\). So \(\frac{3}{5}\) breaks down into three copies of \(\frac{1}{5}\): \(\mathbf{\frac{3}{5}=\frac{1}{5}+\frac{1}{5}+\frac{1}{5}}\).

G4-C04-T01-Q002 About 1 min

Which fraction bar shows \(\frac{4}{6}\) as a sum of unit fractions?

Fraction as Sum of Unit Fractions visual for G4-C04-T01-Q002
  1. A 4 parts shaded, 6 total
  2. B 3 parts shaded, 3 total
  3. C 3 parts shaded, 4 total
  4. D 2 parts shaded, 3 total
Check answer and explanation

Answer A: 4 parts shaded, 6 total

In the fraction bar, we have 4 shaded parts out of 6 equal parts. Each piece is a unit fraction \(\frac{1}{6}\). So we have \(\mathbf{\frac{4}{6}=\underbrace{\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}}_{4 \text{ copies}}}\).

guided

1 question
G4-C04-T01-Q003 About 1 min

What is \(\frac{2}{3}\) as a sum of unit fractions?

  1. A \(\frac{1}{2}+\frac{1}{2}\)
  2. B \(\frac{1}{3}+\frac{1}{3}\)
  3. C \(\frac{2}{3}+\frac{1}{3}\)
  4. D \(\frac{3}{3}\)
Check answer and explanation

Answer B: \(\frac{1}{3}+\frac{1}{3}\)

\(\frac{2}{3}\) means two pieces, each of size \(\frac{1}{3}\). So \(\mathbf{\frac{2}{3}=\frac{1}{3}+\frac{1}{3}}\)—two unit fractions added together.

practice

5 questions
G4-C04-T01-Q004 About 1 min

Sam has a strip of paper divided into 8 equal parts. He colors 5 parts. Which expression shows the fraction colored as a sum of unit fractions?

  1. A \(\frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8}\)
  2. B \(\frac{5}{8}+\frac{5}{8}\)
  3. C \(\frac{1}{5}+\frac{1}{5}+\frac{1}{5}+\frac{1}{5}+\frac{1}{5}\)
  4. D \(\frac{5}{8}\)
Check answer and explanation

Answer A: \(\frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8}\)

Sam colored 5 pieces out of 8 equal parts, so the fraction is \(\frac{5}{8}\). This is the sum of five unit fractions: \(\mathbf{\frac{5}{8}=\underbrace{\frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8}}_{5 \text{ copies}}}\).

G4-C04-T01-Q005 About 1 min

Which number sentence is correct?

  1. A \(\frac{1}{4}+\frac{1}{4}+\frac{1}{4}=\frac{3}{12}\)
  2. B \(\frac{1}{4}+\frac{1}{4}+\frac{1}{4}=\frac{3}{4}\)
  3. C \(\frac{1}{3}+\frac{1}{3}+\frac{1}{3}=\frac{3}{9}\)
  4. D \(\frac{1}{6}+\frac{1}{6}=\frac{2}{12}\)
Check answer and explanation

Answer B: \(\frac{1}{4}+\frac{1}{4}+\frac{1}{4}=\frac{3}{4}\)

When we add unit fractions with the same denominator, we keep the denominator and add the numerators. \(\frac{1}{4}+\frac{1}{4}+\frac{1}{4}\) has three 1's in the numerator, so it equals \(\mathbf{\frac{3}{4}}\). The other choices incorrectly change the denominator.

G4-C04-T01-Q006 About 1 min

Ming shares a pizza cut into 12 equal slices. He eats 3 slices. Show how many slices he ate as a sum of unit fractions.

  1. A \(\frac{3}{12}\)
  2. B \(\frac{1}{12}+\frac{1}{12}+\frac{1}{12}\)
  3. C \(\frac{1}{3}+\frac{1}{3}\)
  4. D \(\frac{3}{3}\)
Check answer and explanation

Answer B: \(\frac{1}{12}+\frac{1}{12}+\frac{1}{12}\)

Ming ate 3 slices out of 12 equal slices, so the fraction is \(\frac{3}{12}\). Breaking this into unit fractions: \(\mathbf{\frac{3}{12}=\frac{1}{12}+\frac{1}{12}+\frac{1}{12}}\)—three slices, each representing \(\frac{1}{12}\) of the pizza.

G4-C04-T01-Q007 About 1 min

A number line shows equal hops from 0 to \(\frac{6}{10}\). How many hops of \(\frac{1}{10}\) are needed?

Fraction as Sum of Unit Fractions visual for G4-C04-T01-Q007
  1. A 3 hops
  2. B 4 hops
  3. C 6 hops
  4. D 10 hops
Check answer and explanation

Answer C: 6 hops

To reach \(\frac{6}{10}\) with hops of \(\frac{1}{10}\), we count: each hop is one unit fraction, and we need 6 copies to equal \(\frac{6}{10}\). So \(\mathbf{6 \text{ hops}}\) gets us there!

G4-C04-T01-Q008 About 1 min

Ava splits a granola bar into 6 equal pieces. She gives away 4 pieces. Write the fraction given away as a sum of unit fractions.

  1. A \(\frac{4}{4}\)
  2. B \(\frac{4}{6}\)
  3. C \(\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}\)
  4. D \(\frac{1}{4}+\frac{1}{4}+\frac{1}{4}+\frac{1}{4}\)
Check answer and explanation

Answer C: \(\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}\)

Ava gave away 4 pieces out of 6 equal pieces, which is \(\frac{4}{6}\). As a sum of unit fractions: \(\mathbf{\frac{4}{6}=\underbrace{\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}}_{4 \text{ copies}}}\).

exit

3 questions
G4-C04-T01-Q009 About 1 min

How many unit fractions of \(\frac{1}{7}\) make \(\frac{5}{7}\)?

  1. A 2
  2. B 5
  3. C 7
  4. D 12
Check answer and explanation

Answer B: 5

\(\frac{5}{7}\) means we have 5 equal pieces, and each piece is \(\frac{1}{7}\). So \(\mathbf{5}\) unit fractions of \(\frac{1}{7}\) make up \(\frac{5}{7}\).

G4-C04-T01-Q010 About 1 min

A number line shows jumps of \(\frac{1}{3}\). Which number of jumps gets us to \(\frac{2}{3}\)?

Fraction as Sum of Unit Fractions visual for G4-C04-T01-Q010
  1. A 1 jump
  2. B 2 jumps
  3. C 3 jumps
  4. D 6 jumps
Check answer and explanation

Answer B: 2 jumps

Each jump moves us forward by \(\frac{1}{3}\). To land on \(\frac{2}{3}\), we need \(\mathbf{2 \text{ jumps}}\): \(\frac{1}{3}+\frac{1}{3}=\frac{2}{3}\).

G4-C04-T01-Q011 About 1 min

Which picture shows \(\frac{3}{4}\) as a sum of unit fractions?

Fraction as Sum of Unit Fractions visual for G4-C04-T01-Q011
  1. A 3 of 4 parts
  2. B 2 of 2 parts
  3. C 4 of 4 parts
  4. D 1 of 2 parts
Check answer and explanation

Answer A: 3 of 4 parts

\(\frac{3}{4}\) shows 3 shaded parts out of 4 equal parts. Since each part is \(\frac{1}{4}\), we have \(\mathbf{\frac{3}{4}=\frac{1}{4}+\frac{1}{4}+\frac{1}{4}}\)—three unit fractions added.

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