Understanding Unit Fractions

Fractions help us describe parts of a whole. When you cut a pizza into equal slices, each slice is a fraction of the entire pizza!

The Parts of a Fraction

A fraction is written with two numbers separated by a line. Each number has a special name and job:

• Denominator (Bottom Number): Tells you how many equal parts the whole is divided into. For example, if a shape is cut into $8$ equal pieces, the denominator is $8$.
• Numerator (Top Number): Tells you how many of those equal parts you have or are looking at.

If you have a shape with $6$ equal parts and $2$ are shaded, the fraction of the shaded part is written as: $\frac{2}{6}$

What is a Unit Fraction?

A unit fraction is a special type of fraction that represents exactly one equal part of a whole. In a unit fraction, the numerator (the top number) is always 1.

Examples of unit fractions include:

• $\frac{1}{2}$ (one half)
• $\frac{1}{4}$ (one fourth)
• $\frac{1}{8}$ (one eighth)

If you eat one slice of a pie that was cut into $4$ equal pieces, you ate $\frac{1}{4}$ of the pie.

Placing Fractions on a Number Line

We can also show fractions on a number line. Let's place the unit fraction $\frac{1}{4}$ on a number line.

1. Start with a whole: Draw a number line starting at $0$ and ending at $1$. The space between $0$ and $1$ represents one whole.
2. Look at the denominator: Since the denominator is $4$, divide the space between $0$ and $1$ into $4$ equal sections.
3. Find your fraction: The numerator is $1$, so you only need to count $1$ space forward from $0$. The very first mark after $0$ is where $\frac{1}{4}$ lives!

Number lines make it easy to see that a fraction like $\frac{1}{4}$ is an actual number that sits right between $0$ and $1$.