Basic 3 · Mathematics · Fractions
Unit Fractions
In this topic you will learn about unit fractions: one equal part of a whole.
By the end of these notes you should be able to:
- Explain what a unit fraction is
- Name unit fractions like ½, ⅓, ¼ and ⅕
- Show unit fractions with shapes and strips
What you already know
- Halves and quarters (Basic 2)
Copy everything that has a blue line on its left into your notebook. The other parts are for reading.
- Strand
- Number
- Sub-strand
- Fractions
- Indicator
- B3.1.3.1.1 – Understand a unit fraction
Introduction
A pizza is cut into 3 equal slices. Each slice is one-third (⅓). One part out of equal parts is a unit fraction.
1. What is a Unit Fraction?
Unit fraction: A fraction with 1 on top. It means one equal part of a whole.
| Fraction | Name | Whole cut into |
|---|---|---|
| ½ | one-half | 2 equal parts |
| ⅓ | one-third | 3 equal parts |
| ¼ | one-quarter | 4 equal parts |
| ⅕ | one-fifth | 5 equal parts |
| ⅙ | one-sixth | 6 equal parts |
2. Parts of a Fraction
In ⅓, the 1 is the numerator: the number of parts we take.
The 3 is the denominator: the number of equal parts in the whole.
Common mistake: The parts must be equal. A cake cut into 3 unequal pieces does not show thirds.
New words
- fraction
- A part of a whole.
- unit fraction
- One equal part, with 1 on top.
- numerator
- The top number of a fraction.
- denominator
- The bottom number of a fraction.
Summary
- A unit fraction has 1 as the numerator.
- The denominator tells how many equal parts make the whole.
- ⅓ means one of three equal parts.
Class activity: Strip Fractions
- Fold a fraction strip into 3 equal parts. Shade ⅓.
- Fold another into 4 equal parts. Shade ¼.
- Label each strip.
You need: Fraction strips cut from old cartons, Bottle tops, Exercise books
Exercises
Answer in your exercise book first, then check your answers.
1. Which is a unit fraction?
- A. ⅓
- B. ⅔
- C. ¾
- D. 2/5
Show answer
Answer: ⅓Its numerator is 1.2. A whole is cut into 6 equal parts. One part is…
- A. ⅙
- B. ⅕
- C. ½
- D. 6
Show answer
Answer: ⅙One of six equal parts.3. ⅕ means one of five equal parts.
- A. True
- B. False
Show answer
Answer: TrueThat is one-fifth.4. In ⅓, the 3 is the numerator.
- A. True
- B. False
Show answer
Answer: False3 is the denominator.5. One of three equal parts is one-______.
Show answer
Answer: third⅓ is one-third.6. Draw a rectangle and shade ⅕ of it.
Show answer
Answer: A rectangle in 5 equal parts with 1 part shaded.One of five equal parts.
Homework
- Find something at home that is divided into equal parts. Name the unit fraction of one part.