Example 1 · level 1
3/5 + 2/3 = ? (write as a fraction in lowest terms)
Show solution
- LCM of 5 and 3 is 15.
- 3/5 = 9/15 and 2/3 = 10/15.
- Add numerators: 19/15.
- Already in lowest terms.
Answer: 19/15
CLASS 8 MATHS · RATIONAL NUMBERS
Add fractions with different denominators
Make the denominators the same (use the LCM), then add the numerators.
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Worked examples
Example 2 · level 2
3/5 + 5/9 = ? (write as a fraction in lowest terms)
Show solution
- LCM of 5 and 9 is 45.
- 3/5 = 27/45 and 5/9 = 25/45.
- Add numerators: 52/45.
- Already in lowest terms.
Answer: 52/45
Example 3 · level 3
3/9 + 6/12 = ? (write as a fraction in lowest terms)
Show solution
- LCM of 9 and 12 is 36.
- 3/9 = 12/36 and 6/12 = 18/36.
- Add numerators: 30/36.
- Simplify: 5/6.
Answer: 5/6