Fractions greater than one (mixed numerals)
Theory
A fraction greater than one can be written as an improper fraction like \(\dfrac{4}{3}\) or as a mixed numeral like \(1\dfrac{1}{3}\). This Year 4 maths page shows how to read them from shapes and number lines, how to change an improper fraction into a mixed numeral and back again, and how to compare amounts greater than one. In Western Australia this is taught in Year 5. Curriculum: VC2M4N04 / AC9M4N04.
An improper fraction has a top number (the numerator) that is the same as or larger than its bottom number (the denominator). It is worth one whole or more, like \(\dfrac{4}{3}\).
A mixed numeral names the same amount as a whole number and a fraction together, like \(1\dfrac{1}{3}\). The whole number counts the full groups and the fraction counts the leftover parts.
The two forms are equal: \(\dfrac{4}{3}=1\dfrac{1}{3}\). Remember that one whole is a fraction with the same top and bottom, so \(\dfrac{4}{4}=1\), \(\dfrac{3}{3}=1\) and \(\dfrac{5}{5}=1\).
These facts help you swap between improper fractions and mixed numerals.
How to change an improper fraction to a mixed numeral
- Find one whole. The denominator tells how many parts make one whole, so \(4\) quarters make a whole.
- Take out the wholes. Count how many full groups of that many parts you have.
- Write the leftover. Put the whole number and the leftover fraction side by side.
To go back the other way, change each whole into parts and add them on: \(2\dfrac{1}{5}=\dfrac{10}{5}+\dfrac{1}{5}=\dfrac{11}{5}\).
How to compare fractions greater than one
- Same bottom number? Compare the top numbers: more parts is the larger amount.
- Use the wholes. Find how many parts make each whole number. In sixths, \(1=\dfrac{6}{6}\), \(2=\dfrac{12}{6}\), \(3=\dfrac{18}{6}\). A fraction is more than that whole number when its top number is bigger.
- Parts still needed. To reach the next whole number, take the parts you have away from the parts in that whole.
| \(\text{one whole}\) | \(=\) | \(\dfrac{5}{5}\) |
| \(\dfrac{5}{5}+\dfrac{3}{5}\) | \(=\) | \(\dfrac{8}{5}\) |
The total is \(\dfrac{8}{5}\).
| \(\dfrac{11}{3}\) | \(=\) | \(\dfrac{9}{3}+\dfrac{2}{3}\) |
| \(\dfrac{9}{3}\) | \(=\) | \(3\) |
| \(\dfrac{11}{3}\) | \(=\) | \(3\dfrac{2}{3}\) |
Three wholes and two thirds: \(3\dfrac{2}{3}\).
| \(2\) | \(=\) | \(\dfrac{10}{5}\) |
| \(2\dfrac{1}{5}\) | \(=\) | \(\dfrac{10}{5}+\dfrac{1}{5}\) |
| \(2\dfrac{1}{5}\) | \(=\) | \(\dfrac{11}{5}\) |
The improper form is \(\dfrac{11}{5}\).
| \(7\text{ halves}\) | \(=\) | \(\dfrac{7}{2}\) |
| \(\dfrac{7}{2}\) | \(=\) | \(\dfrac{6}{2}+\dfrac{1}{2}\) |
| \(\dfrac{7}{2}\) | \(=\) | \(3\dfrac{1}{2}\) |
She has \(3\dfrac{1}{2}\) cups of jelly.
| \(3\text{ wholes}\) | \(=\) | \(3 \times 5 = 15\text{ fifths}\) |
| \(14 < 15,\ \ 15 = 15\) | \(,\) | \(17 > 15\) |
Only \(\dfrac{17}{5}\) is more than 3 wholes. \(\dfrac{15}{5}\) is exactly 3 and \(\dfrac{14}{5}\) is less.
| \(2\dfrac{3}{5}\) | \(=\) | \(\dfrac{10}{5}+\dfrac{3}{5}=\dfrac{13}{5}\) |
| \(3\) | \(=\) | \(\dfrac{15}{5}\) |
| \(15 - 13\) | \(=\) | \(2\) |
He needs 2 more fifths.
Common pitfalls
Frequently asked questions
What is an improper fraction?
An improper fraction has a top number the same as or bigger than the bottom number, so it is worth one whole or more. For example, \(\dfrac{13}{4}\) is thirteen quarters, which is more than three wholes.
What is a mixed numeral?
A mixed numeral is a whole number and a fraction written together, like \(3\dfrac{1}{4}\). It shows the same amount as an improper fraction.
How do you change an improper fraction to a mixed numeral?
Find how many whole groups you can make, then write the leftover as a fraction. For \(\dfrac{13}{4}\), twelve quarters make three wholes and one quarter is left over, so \(\dfrac{13}{4}=3\dfrac{1}{4}\).
How do you change a mixed numeral to an improper fraction?
Change each whole into parts and add on the extra parts. For \(2\dfrac{1}{5}\), two wholes are \(\dfrac{10}{5}\), plus \(\dfrac{1}{5}\) is \(\dfrac{11}{5}\).
Is 13/4 bigger than 3 1/4?
No. They are the same amount written two different ways. \(\dfrac{13}{4}=3\dfrac{1}{4}\).
How many sixths make 2 wholes?
Six sixths make one whole, so two wholes need twelve sixths. That is \(\dfrac{12}{6}\).