💡 How to Use This Lesson
Click any operation card above to jump to that lesson, or use the tabs at the top to navigate. Each lesson shows you step-by-step how it works with a visual model. After all lessons, take the Quiz to test your skills — just like the GED exam!
If the denominators are the same, simply add the numerators and keep the denominator unchanged.
Both fractions have 8 as the denominator. ✅ They match — no conversion needed!
3 + 2 = 5. Keep the denominator 8.
What is 2/9 + 4/9? (Denominators are the same — just add the tops!)
Find the Least Common Denominator (LCD) — the smallest number both denominators divide into evenly. Convert both fractions, then add.
Multiples of 4: 4, 8, 12, 16… | Multiples of 6: 6, 12, 18… → LCD = 12
4 × 3 = 12, so multiply top and bottom by 3: 1×3 / 4×3 = 3/12
6 × 2 = 12, so multiply top and bottom by 2: 1×2 / 6×2 = 2/12
3/12 + 2/12 → 3 + 2 = 5. Keep denominator 12.
What is 1/3 + 1/4? (LCD of 3 and 4 is 12)
When denominators are the same, subtract the numerators and keep the denominator.
Both fractions have 10 as the denominator. ✅ Same denominator!
7 − 3 = 4. Keep the denominator 10.
What is 9/11 − 5/11? (Same denominator — just subtract!)
Just like adding with different denominators — find the LCD, convert both fractions, then subtract.
LCD = 8 (since 4 divides evenly into 8)
4 × 2 = 8, so: 1×2 / 4×2 = 2/8. The fraction 5/8 stays the same.
5 − 2 = 3. Keep denominator 8.
What is 3/4 − 1/8? (LCD = 8)
Write the whole number over 1, then find the LCD and add like normal.
Any whole number over 1: 2 = 2/1
LCD = 5. Convert 2/1 → 10/5 (multiply top and bottom by 5)
10 + 3 = 13. Keep denominator 5.
What is 3 + 2/7? (Convert 3 → 21/7 first)
Convert the whole number to a fraction with the same denominator as the fraction, then subtract.
LCD = 2. Convert 3 → 3/1 → 6/2 (multiply by 2/2)
6 − 1 = 5. Keep denominator 2.
What is 4 − 3/4? (Convert 4 → 16/4)
Numerator × Numerator on top. Denominator × Denominator on bottom. No LCD needed!
2 × 4 = 8
3 × 5 = 15
What is 3/4 × 2/7? (Multiply tops, multiply bottoms)
Keep the first fraction → Change ÷ to × → Flip the second fraction (reciprocal). Then multiply!
3/7 ÷ 2/5 becomes 3/7 × 5/2
3 × 5 = 15
7 × 2 = 14
What is 2/5 × 3/4 ÷ 8/5? (This is the GED question from the screenshot — try it step by step!)