Addition and Subtraction of Fractions Mathematics JSS 1 First Term Lesson Notes Week 8
Addition of Fractions with the Same Denominator
- Keep the denominator the same.
- Add the numerators.
Example:
Keep the denominator (5) the same:
2. Subtraction of Fractions with the Same Denominator
- Keep the denominator the same.
- Subtract the numerators.
Example:
Keep the denominator (8) the same:
3. Addition and Subtraction with Different Denominators
- Find a common denominator.
The common denominator is usually the least common multiple (LCM) of the two denominators.Example:
To add and , the LCM of 3 and 4 is 12. - Convert each fraction to an equivalent fraction with the common denominator.
Example:
- Add or subtract the numerators.
Example:
4. Simplifying Fractions
- Find the greatest common divisor (GCD) of the numerator and denominator.
- Divide both by the GCD.
Example:
(GCD of 8 and 12 is 4)
Examples
- Addition:
Common denominator: 20
- Subtraction:
Common denominator: 10