Formula
This calculator uses the standard fraction calculator formula:
Frequently Asked Questions
Find the Least Common Denominator (LCD), convert each fraction, then add the numerators. For example, 1/2 + 1/3: LCD=6, so 3/6 + 2/6 = 5/6.
Multiply numerators together and denominators together, then simplify. For example, 2/3 × 3/4 = 6/12 = 1/2.
Flip (reciprocal) the second fraction and multiply. For example, 2/3 ÷ 4/5 = 2/3 × 5/4 = 10/12 = 5/6.
Divide both numerator and denominator by their Greatest Common Divisor (GCD). For example, 8/12: GCD=4, so 8/4 ÷ 12/4 = 2/3.
Find the LCD, convert both fractions, subtract the numerators, then simplify. For example, 3/4 − 1/6: LCD=12, so 9/12 − 2/12 = 7/12.
An improper fraction has a numerator greater than or equal to the denominator, e.g. 7/4. It equals the mixed number 1¾.
Understanding Fractions: A Complete Guide
A fraction represents a part of a whole. It has two parts: the numerator (top number) tells how many parts you have, and the denominator (bottom number) tells how many equal parts the whole was divided into. For example, in the fraction 3/4, the denominator 4 means the whole is divided into four equal parts, and the numerator 3 means you are referring to three of those parts. Fractions appear everywhere in everyday life — from cooking measurements (½ cup of sugar) to construction (a 5/8″ drill bit) to time (a quarter past three) to finance (a 3/8% interest rate). Understanding how to add, subtract, multiply, divide, and simplify them is a foundational skill in mathematics and an essential everyday tool.
Types of Fractions
There are several kinds of fractions you will encounter. A proper fraction has a numerator smaller than its denominator (3/4, 7/8, 1/2) and represents a value less than 1. An improper fraction has a numerator equal to or greater than the denominator (5/4, 9/3, 7/7) and represents a value of 1 or more. A mixed number combines a whole number and a proper fraction (1¾, 2⅓) and is just another way of writing an improper fraction — 1¾ equals 7/4 because (1 × 4 + 3) / 4 = 7/4. Equivalent fractions are different-looking fractions that represent the same value: 1/2, 2/4, 3/6, and 50/100 are all equivalent. Like fractions share the same denominator (1/5, 2/5, 4/5), while unlike fractions have different denominators (1/2, 3/5, 7/8).
Adding and Subtracting Fractions
To add or subtract fractions with the same denominator, simply add or subtract the numerators and keep the denominator unchanged: 2/7 + 3/7 = 5/7, and 5/8 − 1/8 = 4/8 = 1/2 (after simplification). To add or subtract fractions with different denominators, first convert them to equivalent fractions sharing a common denominator. The Least Common Denominator (LCD) is the smallest positive integer that is a multiple of both denominators. For 1/4 + 1/6, the LCD is 12 (because 12 is the smallest number both 4 and 6 divide into evenly). Convert each fraction: 1/4 = 3/12 and 1/6 = 2/12. Now add: 3/12 + 2/12 = 5/12. The fraction calculator above does this work for you and shows every step.
Multiplying and Dividing Fractions
Multiplication is the easiest operation on fractions: multiply the numerators together to get the new numerator, and multiply the denominators together to get the new denominator. So 2/3 × 4/5 = (2 × 4) / (3 × 5) = 8/15. Division of fractions works on the rule “invert and multiply”: to divide by a fraction, multiply by its reciprocal (the fraction flipped upside down). So 2/3 ÷ 4/5 = 2/3 × 5/4 = 10/12 = 5/6. A useful sanity check: dividing by a fraction smaller than 1 should give a result larger than the original, and dividing by a fraction larger than 1 should give a smaller result.
Simplifying (Reducing) Fractions
A fraction is in its simplest form when the numerator and denominator share no common factor other than 1. To simplify, find the Greatest Common Divisor (GCD) of the two numbers and divide both by it. For 24/36, the GCD is 12, so 24/36 = (24÷12) / (36÷12) = 2/3. If you don’t know the GCD by inspection, the Euclidean algorithm gives it quickly: gcd(24, 36) → gcd(24, 12) → gcd(12, 0) = 12. The fraction calculator automatically reduces every result to lowest terms and also displays the original unsimplified form so you can see the work.
Converting Between Mixed Numbers and Improper Fractions
To convert a mixed number to an improper fraction, multiply the whole-number part by the denominator and add the numerator; that result is the new numerator, and the denominator stays the same. So 2⅜ = (2 × 5 + 3) / 5 = 13/5. To convert an improper fraction back to a mixed number, divide the numerator by the denominator: the quotient is the whole-number part and the remainder becomes the new numerator. So 17/4 = 4 remainder 1, giving 4¼. Mixed numbers are easier to interpret physically (2¾ pizzas is clearer than 11/4 pizzas), but improper fractions are easier to compute with — so most calculations are done in improper form and converted back at the end.
Practical Worked Example: Recipe Scaling
Suppose a cookie recipe calls for ¾ cup of butter and you want to make 1½ batches. You need to multiply ¾ × 1½ = 3/4 × 3/2 = 9/8 cups = 1⅛ cups of butter. The fraction calculator above performs this kind of mixed-form arithmetic and will return both the improper fraction and the mixed-number form, plus the decimal equivalent (1.125 cups), so you can pick whichever is easier to measure.
Where Fraction Math Matters
Fractions show up far beyond the maths classroom. Carpenters and machinists use them constantly with imperial measurements (5/16″, 7/32″). Cooks adjust recipes by multiplying and dividing fractional measurements. Musicians read fractional time signatures (3/4 waltz, 6/8 jig). Engineers express gear ratios and probability as fractions. Financial professionals quote interest rates and bond prices in fractional eighths and sixteenths. Even in modern decimal-dominated contexts, fractions remain the cleaner way to express exact values that don’t terminate as decimals (1/3 is exact; 0.333... is an approximation). Mastering fraction arithmetic gives you a precision tool that decimals can’t always match.
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