fractions
Subtracting Mixed Numbers
Detailed Example: 3¼ - 1½
1
Convert to improper fractions
3¼ = 13/4 and 1½ = 3/2(3×4+1)/4 = 13/4, (1×2+1)/2 = 3/2
2
Find common denominator
LCD of 4 and 2 is 43/2 = 6/4 (multiply by 2/2)
3
Subtract the numerators
13/4 - 6/4 = 7/4Keep denominator, subtract numerators
4
Convert to mixed number
7/4 = 1¾7 ÷ 4 = 1 remainder 3
3¼ - 1½ = 1¾✓
💡Borrowing When Needed
If the fraction you're subtracting is larger (like 3¼ - 1¾), you may need to "borrow" from the whole number first. Convert one whole to a fraction with the same denominator, then subtract.
More Examples
5⅔ - 2⅓= 3⅓17/3 - 7/3 = 10/3
4½ - 1¾= 2¾9/2 - 7/4 = 18/4 - 7/4 = 11/4
3⅖ - 1⁴⁄₅= 1⅗17/5 - 9/5 = 8/5
⚠️ Common Mistakes
- Forgetting to find a common denominator
- Not borrowing when the top fraction is smaller
- Subtracting denominators (you should keep them the same!)