Add, subtract, multiply, and divide fractions with automatic simplification. Results shown in standard, decimal, and mixed number formats.
Last updated: May 2026 | By Patchworkr Team
| Operation | Expression | Result |
|---|---|---|
| Add | 1/2 + 1/3 | 5/6 |
| Subtract | 3/4 − 1/2 | 1/4 |
| Multiply | 2/3 × 3/4 | 1/2 |
| Divide | 3/4 ÷ 1/2 | 3/2 |
| Simplify | 6/8 | 3/4 |
Fractions represent parts of a whole, expressed as a ratio of numerator (top) to denominator (bottom). Fraction arithmetic combines these ratios through well-defined rules that have been fundamental to mathematics for over 4,000 years. When adding or subtracting fractions, you must first find a common denominator—this represents the smallest unit that both fractions can be expressed in. Multiplication is more direct: multiply the numerators together and the denominators together, then simplify. Division of fractions follows the elegant rule: multiply by the reciprocal (flip the second fraction). All fractional results should be simplified to lowest terms by dividing both numerator and denominator by their greatest common divisor (GCD). This calculator performs all these operations automatically, showing results in three useful formats: simplified proper or improper fractions, and decimal equivalents for practical applications like cooking measurements or financial calculations.
Fractions are essential across numerous fields: in engineering for tolerances and measurements, in medicine for dosage calculations, in cooking for recipe scaling, in music for time signatures and note durations, and in construction for blueprint dimensions. Understanding fraction operations builds foundation for advanced mathematics including algebra, calculus, and statistics. The ability to simplify fractions, find common denominators, and recognize equivalent fractions develops mathematical reasoning that extends far beyond fraction arithmetic itself. Many real-world problems naturally involve fractions—splitting costs, combining recipes, calculating probabilities—making this skill practically valuable throughout life. This calculator bridges manual calculation and modern computation, helping you verify your work and understand the underlying mathematical processes.
Choose whether you want to add, subtract, multiply, or divide fractions from the dropdown menu. This determines which rule applies.
Input the numerator (top number) and denominator (bottom number) of the first fraction. The denominator cannot be zero.
Input the numerator and denominator of the second fraction. For division, this becomes the divisor (the fraction you're dividing by).
Press the Calculate button to compute the result. The calculator automatically applies the correct arithmetic rules and simplifies the answer.
The result appears as a simplified fraction, decimal equivalent, and mixed number (if applicable), helping you interpret the answer in the most useful form.
Adding fractions with different denominators
Find the least common multiple (LCM) of the two denominators. For example, for 3/4 and 1/6, the LCM of 4 and 6 is 12, so you convert both to twelfths.
Simplifying means dividing both numerator and denominator by their greatest common divisor (GCD) until no common factors remain. For example, 6/8 simplifies to 3/4.
A proper fraction has numerator less than denominator (less than 1). An improper fraction has numerator greater than or equal to denominator (1 or more). Both are valid.
A mixed number combines a whole number and a fraction, like 1 3/4. It equals 1 + 3/4. This is useful for expressing improper fractions in everyday contexts.
Division by a fraction is mathematically equivalent to multiplication by its reciprocal. This rule preserves properties of division and makes computation simpler.
No. You must convert to a common denominator first. Adding/subtracting denominators directly is a common mistake that produces incorrect results.
Division by zero is undefined in mathematics. A fraction with zero denominator is impossible and has no value. Always check that your denominator is non-zero.
A fraction is fully simplified when the greatest common divisor of the numerator and denominator is 1 (they share no common factors other than 1).
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