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mathematical reasoningNumber and Algebrafoundation
Mastering Fractions
Understand the basics of fractions, including simplifying, converting between mixed numbers and improper fractions, and finding common denominators.
Key Ideas
- A fraction represents a part of a whole.
- To simplify a fraction, divide both the numerator and denominator by their greatest common divisor.
- To add or subtract fractions, you must find a common denominator first.
- Multiplying fractions: multiply numerators together and denominators together.
- Dividing fractions: Keep, Change, Flip (multiply by the reciprocal).
Worked Examples
Example 1
Calculate 2/3 + 1/4.
Explanation
Find a common denominator for 3 and 4. The lowest common multiple is 12.
Convert 2/3 to twelfths: (2 × 4) / (3 × 4) = 8/12.
Convert 1/4 to twelfths: (1 × 3) / (4 × 3) = 3/12.
Add the numerators: 8/12 + 3/12 = 11/12.
Example 2
Simplify 18/24.
Explanation
Find the factors of 18: 1, 2, 3, 6, 9, 18.
Find the factors of 24: 1, 2, 3, 4, 6, 8, 12, 24.
The greatest common factor is 6.
Divide numerator and denominator by 6: 18 ÷ 6 = 3, and 24 ÷ 6 = 4.
The simplified fraction is 3/4.
Ready to Practice?
Common Mistakes
- ×Adding denominators together (e.g., 1/2 + 1/2 = 2/4).
- ×Forgetting to simplify the final answer.
- ×Confusing the method for multiplying fractions with adding them.
Exam Tip
"When dealing with mixed numbers in calculations, it's often safer to convert them to improper fractions first."