Guide
What Is a Unit Fraction?
Unit fractions are the simple building blocks all other fractions are made from.
Unit fractions are the simple building blocks all other fractions are made from.
Definition of a unit fraction
A unit fraction is any fraction whose numerator is 1, such as 1/2, 1/3, 1/4 or 1/100. Each one represents a single equal part of a whole.
Why unit fractions are special
Every fraction is built from unit fractions. 3/4 is just three copies of the unit fraction 1/4. Thinking this way makes adding and comparing fractions more intuitive.
Comparing unit fractions
With unit fractions, the bigger the denominator, the smaller the fraction — because the whole is cut into more, smaller pieces. So 1/3 is larger than 1/8.
Where unit fractions appear
They show up constantly: half a cup (1/2), a quarter of an hour (1/4), a tenth of a metre (1/10). Ancient Egyptian maths was built almost entirely on unit fractions.
Related tools & guides
Frequently asked
What is a unit fraction?
A fraction with 1 as its numerator, such as 1/2, 1/5 or 1/20. It represents one equal part of a whole.
Is 2/5 a unit fraction?
No. A unit fraction must have a numerator of exactly 1, so 2/5 is not a unit fraction but 1/5 is.
Which is bigger, 1/4 or 1/6?
1/4 is bigger. With unit fractions, a smaller denominator means larger pieces.