Compare & order fractions (denom 2,3,4,5,6,8,10)
Theory
To compare fractions, make them easy to match. With the same denominator, compare the numerators; with the same numerator, the smaller denominator gives bigger parts; otherwise compare with one half or rename both with a common denominator. This Year 6 maths page shows each method and how to order several fractions.
Same denominator: the parts are the same size, so more parts is bigger. \(\dfrac{4}{5} > \dfrac{2}{5}\).
Same numerator: the same number of parts, but a smaller denominator means bigger parts. \(\dfrac{2}{3} > \dfrac{2}{5}\).
Benchmark one half: a fraction is more than a half when its numerator is more than half its denominator. \(\dfrac{4}{6} > \dfrac{1}{2}\) and \(\dfrac{3}{10} < \dfrac{1}{2}\).
Common denominator: rename both fractions with the same denominator (a multiple of both), then compare numerators. \(\dfrac{3}{4} = \dfrac{9}{12}\) and \(\dfrac{4}{6} = \dfrac{8}{12}\).
Ways to compare:
| Fractions | Method |
|---|---|
| same denominator | larger numerator is larger |
| same numerator | smaller denominator is larger |
| one each side of a half | compare with one half |
| anything else | rename with a common denominator |
How to compare two fractions
- Check for the same denominator or the same numerator.
- Try the benchmark one half.
- Otherwise rename both with a common denominator and compare the numerators.
- Write the answer with \(>\), \(<\) or \(=\).
How to order several fractions
- Rename them all with one common denominator.
- Order the numerators, then write the original fractions in that order.
| \(\dfrac{2}{5}\) | \(<\) | \(\dfrac{4}{5}\) |
Same-sized parts: \(2 < 4\).
| \(\dfrac{2}{3}\) | \(>\) | \(\dfrac{2}{5}\) |
Thirds are bigger than fifths, so \(\dfrac{2}{3}\) (first diagram).
\(3\) is less than half of \(10\); \(4\) is more than half of \(6\).
| \(\dfrac{3}{10}\) | \(<\) | \(\dfrac{1}{2} < \dfrac{4}{6}\) |
\(\dfrac{4}{6}\).
More parts means smaller parts: \(\dfrac{1}{10}, \dfrac{1}{5}, \dfrac{1}{3}\).
| \(\dfrac{3}{4}\) | \(=\) | \(\dfrac{9}{12}\) |
| \(\dfrac{4}{6}\) | \(=\) | \(\dfrac{8}{12}\) |
\(9 > 8\), so \(\dfrac{3}{4} > \dfrac{4}{6}\).
| \(\dfrac{2}{3}\) | \(=\) | \(\dfrac{20}{30}\) |
| \(\dfrac{7}{10}\) | \(=\) | \(\dfrac{21}{30}\) |
\(\dfrac{7}{10}\), by just \(\dfrac{1}{30}\).
In tenths: \(\dfrac{6}{10}\), \(\dfrac{5}{10}\), \(\dfrac{7}{10}\), \(\dfrac{2}{10}\).
\(\dfrac{1}{5}, \dfrac{1}{2}, \dfrac{3}{5}, \dfrac{7}{10}\) (see the number line).
| \(\dfrac{3}{8}\) | \(=\) | \(\dfrac{9}{24}\) |
| \(\dfrac{1}{3}\) | \(=\) | \(\dfrac{8}{24}\) |
Jo.
| \(\dfrac{3}{10}\) | \(<\) | \(\dfrac{3}{6}\) |
Both have \(3\) parts, but tenths are smaller than sixths, so \(\dfrac{3}{6}\) is larger.
Common pitfalls
Frequently asked questions
How do I compare fractions with the same denominator?
Compare the numerators: more parts of the same size is bigger.
How do I compare fractions with the same numerator?
The one with the smaller denominator is bigger, because its parts are bigger.
What is a common denominator?
A number that both denominators divide into, such as 12 for quarters and sixths.
How can one half help?
If one fraction is less than a half and the other is more, you can tell which is bigger straight away.
How do I order fractions?
Rename them all with one common denominator and order the numerators.