CH03-03 lesson

Representing 1/b on a Number Line Learning Activity

A focused Grade 3 learning session for Representing 1/b on a Number Line using visual models, worked examples, strategy guidance, and a short mastery check.

15
minutes
6
lesson parts
11
practice items
Learning goal

Students will represent a unit fraction on a number line by partitioning the whole into equal lengths.

Student goal: I can represent one equal part on a number line as a unit fraction.

concept

Learn the Idea

Representing 1/b on a Number Line means using place value, operations, and equations to reason accurately with numbers.

  • Read the question carefully and identify what is being asked.
  • Choose a model, equation, table, or diagram that matches the situation.
  • Solve one step at a time and keep units or labels attached.
  • Use the answer explanation to check that the result makes sense.
visual model

See the Math

Visual Model 1

Question: A number line from \(0\) to \(1\) is divided into \(4\) equal parts. Which fraction names the first tick mark after \(0\)?

Grade 3 Representing 1/b on a Number Line figure 1

  • A. \(\frac{1}{4}\)
  • B. \(\frac{1}{2}\)
  • C. \(\frac{1}{3}\)
  • D. \(\frac{2}{4}\)

Why it works: The first tick is at one of four equal parts, which is \(\frac{1}{4}\).

Answer: \(\frac{1}{4}\)

worked example

Follow a Worked Example

Example 1

Question: A number line from \(0\) to \(1\) is split into \(8\) equal parts. Mark where \(\frac{1}{8}\) is located. Which tick mark shows \(\frac{1}{8}\)?

Grade 3 Representing 1/b on a Number Line figure 3

  • A. The second tick
  • B. The first tick
  • C. The middle tick
  • D. The last tick
  1. The number line has 8 equal parts, so the first tick is at \(\frac{1}{8}\).

Answer: The first tick after 0 is \(\frac{1}{8}\).

Example 2

Question: Look at this number line with \(0\) to \(1\) divided into \(6\) equal parts: What fraction is the first tick labeled by the question mark?

Grade 3 Representing 1/b on a Number Line figure 4

  • A. \(\frac{1}{6}\)
  • B. \(\frac{1}{5}\)
  • C. \(\frac{1}{3}\)
  • D. \(\frac{2}{6}\)
  1. Six equal parts means each is \(\frac{1}{6}\).

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

real world

Connect It to a Real Situation

Problem 1

Question: A piece of ribbon is divided into \(2\) equal lengths on a number line from \(0\) to \(1\). What is the unit fraction?

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

Why it works: Two equal parts gives unit fraction \(\frac{1}{2}\).

Answer: \(\frac{1}{2}\)

strategy

Avoid Mistakes and Choose a Strategy

  • Rushing before identifying what the numbers represent.
  • Choosing an operation that does not match the situation.
  • Dropping labels, units, or context from the answer.
  • Skipping the estimate or reasonableness check.
  • Underline the question being asked.
  • Use a model before jumping to computation.
  • Write an equation that matches the story or picture.
  • Explain the final answer in a sentence.
summary

Remember the Key Idea

Representing 1/b on a Number Line becomes easier when students connect the question to a model, use clear steps, and explain why the answer fits.

GOLDEN RULE

Understand the model before choosing the operation.

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
G3-C03-T03-Q001 About 1 min

A number line from \(0\) to \(1\) is divided into \(5\) equal parts. What is the length of each part?

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

Answer A: \(\frac{1}{5}\)

When the interval from \(0\) to \(1\) is split into \(5\) equal parts, each part has length \(\frac{1}{5}\).

G3-C03-T03-Q002 About 1 min

A number line from \(0\) to \(1\) is divided into \(4\) equal parts. Which fraction names the first tick mark after \(0\)?

Representing 1/b on a Number Line visual for G3-C03-T03-Q002
  1. A \(\frac{1}{4}\)
  2. B \(\frac{1}{2}\)
  3. C \(\frac{1}{3}\)
  4. D \(\frac{2}{4}\)
Check answer and explanation

Answer A: \(\frac{1}{4}\)

The first tick is at one of four equal parts, which is \(\frac{1}{4}\).

guided

1 question
G3-C03-T03-Q003 About 1 min

If a number line from \(0\) to \(1\) is split into \(3\) equal parts, what fraction marks the first partition?

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

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

Splitting from \(0\) to \(1\) into three equal parts gives \(\frac{1}{3}\) for each.

practice

5 questions
G3-C03-T03-Q004 About 1 min

A number line shows \(0\) and \(1\) divided in half (into 2 equal parts). The first tick mark is at which fraction?

Representing 1/b on a Number Line visual for G3-C03-T03-Q004
  1. A \(\frac{1}{2}\) (the unit fraction)
  2. B \(\frac{1}{3}\) (wrong denominator)
  3. C \(\frac{2}{2}\) (the whole)
  4. D \(\frac{1}{4}\) (too many parts)
Check answer and explanation

Answer A: \(\frac{1}{2}\) (the unit fraction)

Divided in half means 2 equal parts. The first tick is at the unit fraction \(\frac{1}{2}\).

G3-C03-T03-Q005 About 1 min

A number line from \(0\) to \(1\) is divided into \(6\) equal parts. What is the distance between \(0\) and the first tick?

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

Answer A: \(\frac{1}{6}\)

When dividing into 6 equal parts, each part is \(\frac{1}{6}\) of the whole.

G3-C03-T03-Q006 About 1 min

A number line from \(0\) to \(1\) is split into \(8\) equal parts. Mark where \(\frac{1}{8}\) is located. Which tick mark shows \(\frac{1}{8}\)?

Representing 1/b on a Number Line visual for G3-C03-T03-Q006
  1. A The second tick
  2. B The first tick
  3. C The middle tick
  4. D The last tick
Check answer and explanation

Answer B: The first tick

The number line has 8 equal parts, so the first tick is at \(\frac{1}{8}\).

G3-C03-T03-Q007 About 1 min

Sam divides a number line from \(0\) to \(1\) into \(4\) equal parts. How many parts are between \(0\) and the second tick mark?

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

Answer B: 2

The second tick is two of the four equal parts from \(0\).

G3-C03-T03-Q008 About 1 min

Look at this number line with \(0\) to \(1\) divided into \(6\) equal parts: What fraction is the first tick labeled by the question mark?

Representing 1/b on a Number Line visual for G3-C03-T03-Q008
  1. A \(\frac{1}{6}\)
  2. B \(\frac{1}{5}\)
  3. C \(\frac{1}{3}\)
  4. D \(\frac{2}{6}\)
Check answer and explanation

Answer A: \(\frac{1}{6}\)

Six equal parts means each is \(\frac{1}{6}\).

exit

3 questions
G3-C03-T03-Q009 About 1 min

Ava draws two number lines from \(0\) to \(1\). One is split into \(3\) equal parts; the other is split into \(4\) equal parts. Which unit fraction represents a smaller piece?

  1. A \(\frac{1}{3}\)
  2. B \(\frac{1}{4}\)
  3. C Both are equal
  4. D Cannot tell
Check answer and explanation

Answer B: \(\frac{1}{4}\)

More parts means smaller pieces. When the same line is split into more parts, each part is smaller. \(\frac{1}{4} < \frac{1}{3}\).

G3-C03-T03-Q010 About 1 min

A ribbon is marked on a number line from \(0\) to \(1\) with \(8\) equal spaces. Mia marks the first space. What fraction of the ribbon is marked?

Representing 1/b on a Number Line visual for G3-C03-T03-Q010
  1. A \(\frac{1}{8}\)
  2. B \(\frac{1}{7}\)
  3. C \(\frac{1}{9}\)
  4. D \(\frac{2}{8}\)
Check answer and explanation

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

One of eight equal spaces is \(\frac{1}{8}\).

G3-C03-T03-Q011 About 1 min

Noah splits a number line from \(0\) to \(1\) into \(2\) equal parts. Then he splits each part in half again. How many equal parts are there now?

  1. A 2
  2. B 3
  3. C 4
  4. D 8
Check answer and explanation

Answer C: 4

Two parts split in half each gives 2 × 2 = 4 parts.

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