Mixed numbers (AQA GCSE Maths): Revision Notes
Mixed numbers
What are mixed numbers?
Mixed numbers contain both a whole number part and a fraction part. They represent quantities that are more than one whole but not quite the next whole number.
For example, is a mixed number where:
- 3 is the whole number part
- is the fraction part
- The mixed number represents
Improper fractions are fractions where the numerator (top number) is larger than the denominator (bottom number). Examples include , , and .
Mixed numbers and improper fractions represent the same values but in different forms, making them interchangeable representations of quantities greater than one.
Understanding the relationship between mixed numbers and improper fractions is fundamental to working with fractions effectively. Both forms have their advantages depending on the mathematical operation you're performing.
Converting mixed numbers to improper fractions
To change a mixed number into an improper fraction, you need to combine the whole number and fraction parts into a single fraction.
Steps for conversion:
- Multiply the whole number by the denominator
- Add the result to the numerator
- Keep the same denominator
Worked Example: Converting to an improper fraction
Step 1: Multiply the whole number by the denominator
Step 2: Add the result to the numerator
Step 3: Keep the same denominator
Therefore:
Converting improper fractions to mixed numbers
To change an improper fraction into a mixed number, you need to separate the whole number part from the remaining fraction.
Steps for conversion:
- Divide the numerator by the denominator
- The whole number part is the quotient
- The remainder becomes the new numerator
- Keep the same denominator
Worked Example: Converting to a mixed number
Step 1: Divide the numerator by the denominator remainder
Step 2: Write as a mixed number
- Whole number part:
- Remainder as numerator:
- Keep denominator:
Therefore:
Golden rule for calculations
Always convert mixed numbers to improper fractions before doing any calculations. This makes multiplication, division, addition and subtraction much easier and more accurate.
Converting first eliminates the complexity of working with both whole numbers and fractions simultaneously, reducing the chance of errors.
Working with mixed numbers in calculations
When performing calculations with mixed numbers, the key strategy is to convert to improper fractions first, perform the calculation, then convert back if needed.
Multiplication example
Worked Example: Calculating
Step 1: Convert to improper fraction
Step 2: Multiply
Step 3: Convert back to mixed number
Subtraction example
Worked Example: Calculating
Step 1: Convert both to improper fractions and
Step 2: Subtract
Step 3: Convert back to mixed number
Division with real-world context
When dividing mixed numbers, convert to improper fractions first, then use the "flip and multiply" rule.
Worked Example: Sharing pizzas equally
Problem: Someone has pizzas and wants to divide them equally between 3 people.
Step 1: Convert to improper fraction
Step 2: Divide using "flip and multiply"
Answer: Each person receives of a pizza.
Steps for adding or subtracting mixed numbers
Complete process for addition and subtraction:
- Write both numbers as improper fractions
- Write both fractions with the same denominator (find equivalent fractions)
- Add or subtract the numerators
- If your answer is an improper fraction, convert it back to a mixed number
Remember that having common denominators is essential before you can add or subtract the fractions.
Exam tips
Essential exam strategies:
- You cannot use a calculator for mixed number questions in many exams
- Always show your working clearly - marks are often awarded for method
- Check your final answer makes sense in the context of the problem
- Remember to convert back to mixed numbers if the question asks for that format
- Double-check conversions between mixed numbers and improper fractions
Key Points to Remember:
- Mixed numbers have a whole number part and a fraction part
- Improper fractions have numerators larger than denominators
- Always convert to improper fractions before calculations
- Use multiply and add to convert mixed to improper
- Use divide with remainder to convert improper to mixed
- Show all working steps in exam questions