What a fraction shows
A fraction shows equal parts of a whole. In ¾ the bottom number (denominator) tells how many equal parts, and the top number (numerator) tells how many we take.
Key idea
To add or subtract fractions with the same denominator, keep the denominator and add or subtract only the top numbers.
Worked example
Worked example
Work out ½ + ¼.
Change ½ into quarters: ½ = 2/4.
Now add: 2/4 + 1/4 = ¾.
Equivalent fractions
Two fractions can name the same amount. ½ and 2/4 are equal. We can also simplify a fraction: 4/8 = ½ by dividing the top and bottom by 4. To compare two fractions, it helps to give them the same denominator first, then just compare the top numbers. For example, ¾ = 3/4 and ½ = 2/4, so ¾ is larger because 3 is more than 2. Finding a fraction of an amount is easy too: ½ of 12 means 12 ÷ 2 = 6.
Remember
- Same denominator? Just work with the top numbers.
- Different denominators? Make them the same first.
- Simplify by dividing top and bottom by the same number.