Fractions: Thirds
Explore thirds as equal parts of shapes and collections, and compare thirds to halves and quarters.
What You Need to Know
Key Concept Diagram
A third divides a whole into 3 equal parts; each part is written as ⅓.
Three thirds make one whole: ⅓ + ⅓ + ⅓ = 1.
To find a third of a number, divide by 3 (e.g. ⅓ of 12 = 4).
Thirds, halves, and quarters can be compared on a number line from 0 to 1.
Key Vocabulary
third
One of three equal parts of a whole, written as ⅓.
whole
A complete undivided quantity or shape.
number line
A line with equally spaced marks used to show and compare numbers and fractions.
compare
To decide if one quantity is greater than, less than, or equal to another.
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
A ribbon is cut into 3 equal pieces. What fraction is each piece?
Question 2
What is ⅓ of 18?
Question 3
Which is larger: ⅓ or ¼?
Key Concepts Summary
- ●A third divides a whole into 3 equal parts; each part is written as ⅓.
- ●Three thirds make one whole: ⅓ + ⅓ + ⅓ = 1.
- ●To find a third of a number, divide by 3 (e.g. ⅓ of 12 = 4).
- ●Thirds, halves, and quarters can be compared on a number line from 0 to 1.