Let's solve each problem step by step to find the
Least Common Denominator (LCD) for each pair of fractions.
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🔷 What is the LCD?
The
Least Common Denominator is the
least common multiple (LCM) of the denominators of two or more fractions. It allows you to rewrite fractions with the same denominator so they can be added, subtracted, or compared.
We'll find the LCM of the denominators in each pair.
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✔ Step-by-step Solutions:
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#### a) $ \frac{1}{6} $ and $ \frac{2}{3} $
- Denominators: 6 and 3
- Multiples of 6: 6, 12, 18...
- Multiples of 3: 3, 6, 9, 12...
-
LCM = 6
✔ LCD = 6
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#### b) $ \frac{1}{4} $ and $ \frac{5}{6} $
- Denominators: 4 and 6
- Multiples of 4: 4, 8, 12, 16...
- Multiples of 6: 6, 12, 18...
-
LCM = 12
✔ LCD = 12
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#### c) $ \frac{5}{8} $ and $ \frac{4}{9} $
- Denominators: 8 and 9
- 8 = $ 2^3 $
- 9 = $ 3^2 $
- LCM = $ 2^3 \times 3^2 = 8 \times 9 = 72 $
✔ LCD = 72
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#### d) $ \frac{1}{6} $ and $ \frac{2}{9} $
- Denominators: 6 and 9
- 6 = $ 2 \times 3 $
- 9 = $ 3^2 $
- LCM = $ 2 \times 3^2 = 2 \times 9 = 18 $
✔ LCD = 18
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#### e) $ \frac{2}{5} $ and $ \frac{1}{8} $
- Denominators: 5 and 8
- 5 is prime, 8 = $ 2^3 $
- LCM = $ 5 \times 8 = 40 $
✔ LCD = 40
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#### f) $ \frac{5}{6} $ and $ \frac{2}{3} $
- Denominators: 6 and 3
- 6 is divisible by 3 → LCM = 6
✔ LCD = 6
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#### g) $ \frac{1}{5} $ and $ \frac{2}{3} $
- Denominators: 5 and 3
- Both are prime → LCM = $ 5 \times 3 = 15 $
✔ LCD = 15
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#### h) $ \frac{1}{2} $ and $ \frac{1}{4} $
- Denominators: 2 and 4
- 4 is divisible by 2 → LCM = 4
✔ LCD = 4
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#### i) $ \frac{3}{10} $ and $ \frac{1}{5} $
- Denominators: 10 and 5
- 10 is divisible by 5 → LCM = 10
✔ LCD = 10
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#### j) $ \frac{7}{8} $ and $ \frac{4}{10} $
- Denominators: 8 and 10
- 8 = $ 2^3 $
- 10 = $ 2 \times 5 $
- LCM = $ 2^3 \times 5 = 8 \times 5 = 40 $
✔ LCD = 40
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#### k) $ \frac{1}{6} $ and $ \frac{2}{4} $
- Simplify $ \frac{2}{4} = \frac{1}{2} $, but we still use original denominators.
- Denominators: 6 and 4
- 6 = $ 2 \times 3 $
- 4 = $ 2^2 $
- LCM = $ 2^2 \times 3 = 4 \times 3 = 12 $
✔ LCD = 12
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#### l) $ \frac{8}{9} $ and $ \frac{2}{3} $
- Denominators: 9 and 3
- 9 is divisible by 3 → LCM = 9
✔ LCD = 9
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✔ Final Answers:
| Problem | LCD |
|--------|-----|
| a) | 6 |
| b) | 12 |
| c) | 72 |
| d) | 18 |
| e) | 40 |
| f) | 6 |
| g) | 15 |
| h) | 4 |
| i) | 10 |
| j) | 40 |
| k) | 12 |
| l) | 9 |
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🎉 How Did You Do?
You can now fill in the blanks on the worksheet!
>
Answer Key:
> a) 6
> b) 12
> c) 72
> d) 18
> e) 40
> f) 6
> g) 15
> h) 4
> i) 10
> j) 40
> k) 12
> l) 9
And don't forget to smile! 😊😊😊
Let me know if you'd like help converting these fractions to equivalent forms using the LCD!
Parent Tip: Review the logic above to help your child master the concept of finding common denominators worksheet.