Half — Definition, Formula & Examples
Half is one of two equal parts that make up a whole. As a fraction, half is written as .
Half denotes the quantity obtained by dividing a whole into exactly two parts of equal size, represented by the fraction , the decimal , or the ratio between the two parts.
Key Formula
Where:
- = The number or quantity you want to find half of
How It Works
To find half of a number, divide it by 2. For example, half of 10 is . You can also think of it as multiplying by , which gives the same result. Two halves always combine to make one whole: .
Worked Example
Problem: A pizza has 8 slices. You eat half the pizza. How many slices did you eat?
Set up: Find half of 8 by dividing by 2.
Divide: 8 divided by 2 equals 4.
Answer: You ate 4 slices.
Why It Matters
Half is one of the first fractions students learn and appears constantly in everyday life — splitting things fairly, reading clocks, and measuring ingredients. Understanding half builds the foundation for working with all other fractions.
Common Mistakes
Mistake: Thinking half means any two pieces, even if they are not equal in size.
Correction: Both pieces must be exactly the same size. Cutting a sandwich into a big piece and a small piece does not make two halves.