✦ Step-by-Step Solutions

Fraction Calculator

Add, subtract, multiply, and divide fractions with step-by-step solutions. Automatic simplification and mixed number conversion.

💡 Quick Answer: 1/3 + 1/4 = 7/12. How? Find LCD (12), convert: 4/12 + 3/12 = 7/12. For multiplication: 2/3 × 3/4 = 6/12 = 1/2. No common denominator needed.
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📚 Method: Euclidean Algorithm for GCD (Greatest Common Divisor) — the most efficient method for fraction simplification, known since 300 BC.

How Do You Add Fractions?

To add fractions, find a common denominator, convert both fractions, add the numerators, and simplify. Example: 1/3 + 1/4 → LCD is 12 → 4/12 + 3/12 = 7/12.

If the denominators are the same, simply add the numerators: 2/5 + 1/5 = 3/5. If different, find the Least Common Denominator (LCD), which is the smallest number both denominators divide into evenly. This calculator finds the LCD and shows each step automatically.

How Do You Multiply and Divide Fractions?

To multiply: multiply numerators together and denominators together. To divide: multiply by the reciprocal (flip the second fraction).

Multiplication: 2/3 × 3/4 = 6/12 = 1/2. Division uses "Keep, Change, Flip": 2/3 ÷ 4/5 → keep 2/3, change ÷ to ×, flip 4/5 to 5/4 → 2/3 × 5/4 = 10/12 = 5/6. No common denominator is needed for either operation.

How Do You Simplify a Fraction?

Divide both the numerator and denominator by their Greatest Common Divisor (GCD). Example: 18/24 → GCD is 6 → 18÷6 / 24÷6 = 3/4.

A fraction is in simplest form when the only common factor of the numerator and denominator is 1. To find the GCD, you can list factors or use the Euclidean algorithm (which this calculator uses). If the result is an improper fraction (numerator > denominator), it's also converted to a mixed number.

How to Add and Subtract Fractions

To add or subtract fractions, they must have the same denominator (bottom number). If they don't, find the Least Common Denominator (LCD), convert both fractions, then add or subtract the numerators.

Same denominator: a/c ± b/c = (a ± b)/c
Different denominators: a/b ± c/d = (a×d ± c×b) / (b×d), then simplify
📝 Example
2/3 + 3/4: LCD = 12 → 8/12 + 9/12 = 17/12 = 1 5/12
5/6 − 1/4: LCD = 12 → 10/12 − 3/12 = 7/12
The cross-multiplication shortcut (a/b + c/d = (ad + bc)/bd) always works but may give a non-simplified result. For example: 1/2 + 1/3 = (3+2)/6 = 5/6. To simplify any fraction, divide both numerator and denominator by their GCD (Greatest Common Divisor).

How to Multiply and Divide Fractions

Multiplication is the easiest fraction operation: multiply straight across (numerator × numerator, denominator × denominator). Division flips the second fraction and multiplies.

Multiply: a/b × c/d = (a×c) / (b×d)
Divide: a/b ÷ c/d = a/b × d/c = (a×d) / (b×c)
📝 Examples
Multiply: 2/3 × 4/5 = 8/15
Divide: 3/4 ÷ 2/5 = 3/4 × 5/2 = 15/8 = 1 7/8
Pro tip — cross-cancel before multiplying to keep numbers small. In 4/9 × 3/8: the 4 and 8 share factor 4 (simplify to 1/9 × 3/2), and the 9 and 3 share factor 3 (simplify to 1/3 × 1/2) = 1/6. Much easier than multiplying 4×3=12, 9×8=72, then reducing 12/72.

Converting Between Fractions, Decimals, and Percentages

Fractions, decimals, and percentages are three ways to express the same value. Converting between them is a fundamental math skill used in cooking, finance, construction, and everyday life.

Fraction → Decimal: Divide numerator by denominator. 3/4 = 3 ÷ 4 = 0.75
Decimal → Percentage: Multiply by 100. 0.75 × 100 = 75%
Percentage → Fraction: Put over 100 and simplify. 75% = 75/100 = 3/4
Decimal → Fraction: Use place value. 0.375 = 375/1000 = 3/8
FractionDecimalPercent
1/80.12512.5%
1/40.2525%
1/30.333…33.3%
1/20.550%
2/30.667…66.7%
3/40.7575%
7/80.87587.5%
Memorizing these common equivalents makes mental math significantly faster in everyday situations like cooking ("half of 3/4 cup"), shopping ("what's 1/3 off?"), and construction ("what's 5/8 inch in decimal?").

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By Claudia-Elena Linul — AEO Business Strategist

Note: This calculator works with integers only. For decimal-to-fraction conversion, multiply both parts by a power of 10 first (e.g., 0.75 = 75/100 = 3/4). Negative fractions are supported — enter a negative numerator.


How to Calculate Fractions: A Complete Guide with Step-by-Step Examples

Fractions represent parts of a whole and are one of the most fundamental concepts in mathematics. Whether you are a student learning arithmetic, a cook adjusting recipes, a carpenter measuring wood, or an engineer calculating tolerances, understanding fraction operations is an essential life skill. This calculator handles all four operations with automatic simplification and step-by-step explanations.

Adding and Subtracting Fractions: The Common Denominator Method

To add fractions, you must first find a common denominator — a number that both denominators divide into evenly. The most efficient approach is to use the Least Common Denominator (LCD). For 1/3 + 1/4: the LCD of 3 and 4 is 12. Convert: 4/12 + 3/12 = 7/12. For subtraction, the process is identical except you subtract the numerators: 3/4 - 1/3 = 9/12 - 4/12 = 5/12.

Multiplying and Dividing: Simpler Than You Think

Multiplication is the simplest fraction operation: multiply numerators together and denominators together. 2/3 × 3/4 = 6/12 = 1/2. No common denominator needed. Division uses the "Keep, Change, Flip" rule: keep the first fraction, change ÷ to ×, flip the second fraction. 2/3 ÷ 4/5 = 2/3 × 5/4 = 10/12 = 5/6.

Simplification Using the GCD (Greatest Common Divisor)

A fraction is in simplest form when the only common factor of the numerator and denominator is 1. To simplify, divide both by their GCD. This calculator uses the Euclidean Algorithm (the most efficient method, known since 300 BC by the Greek mathematician Euclid) to find the GCD automatically. For 18/24: GCD(18,24) = 6, so 18÷6 / 24÷6 = 3/4. Improper fractions (numerator > denominator) are also converted to mixed numbers: 7/4 = 1 3/4.