Fractions
Maths: Edexcel IGCSE Higher, topic 1.2.1
Fractions
You need to know how to multiply, divide, add and subtract fractions.
Multiplying fractions
- To multiply two fractions together, multiply the tops together and the bottoms together.
- Remember to cancel down as much as possible by dividing top and bottom by the same number.
Dividing fractions
- To divide a fraction by another fraction, flip the second fraction and then multiply.
Adding or subtracting fractions
- To add or subtract two fractions first write them with the same denominator and then add or subtract the top numbers only.
Comparing Fractions
Which is bigger: 5⁄6 or 7⁄8?
Write fractions so they have the same denominator
21 is bigger than 20
Therefore 7⁄8 is bigger than 5⁄6
Mixed Numbers and Improper Fractions
Mixed numbers and improper fractions are both greater than 1.
Improper fractions
- An improper fraction has a numerator (top number) which is larger than the denominator (bottom number).
- E.g. 9 is larger than 7, so is an improper fraction.
Mixed numbers
- A mixed number contains both a whole number (an integer) and a normal fraction.
Improper fraction to mixed number
- What is written as a mixed number?
Improper fraction to mixed number
- First work out how many times the denominator will go into the numerator.
- 9 goes into 26 two times - this is the whole number part.
Improper fraction to mixed number
- The remainder is 26 − 18 = 8.
- So the fraction part is .
Mixed number to improper fraction
- What is 3 written as an improper fraction?
Mixed number to improper fraction
- Multiply the whole number by the denominator.
- Add this amount to the numerator.
Mixed number to improper fraction
- Finish the addition.
Test yourself on Fractions
What is 4⁄5 × 7⁄2?
What is 5⁄2 × 7⁄2?
What is 1⁄3 × 4⁄5?
Ordering Numbers
Which of these fractions are larger?