Fraction arithmetic, decimal-to-fraction conversion, ratios and proportions. Use the calculators for your own numbers and the guides for formulas, examples and common questions.
Use the tool that matches the exact problem you need to solve.
Add, subtract, multiply or divide two fractions and reduce the result to lowest terms.
Convert a terminating decimal to a reduced fraction and mixed number.
Simplify a ratio of two whole numbers to lowest terms.
Solve a proportion of the form a/b = c/d when one of the four values is unknown.
Find the least common multiple of two or more whole numbers.
Find the greatest common factor (greatest common divisor) of two or more whole numbers.
Break a positive whole number into its prime factors.
Convert a number to normalized scientific notation and evaluate a coefficient times a power of ten.
Three long-tail answers that explain formulas and common scenarios behind this calculator cluster.
Learn how to add or subtract fractions by finding a common denominator and simplifying the result.
Read guide →Fractions, Ratios & ProportionsLearn how to turn a terminating decimal into a fraction using place value and reducing to lowest terms.
Read guide →Fractions, Ratios & ProportionsLearn how to solve proportions with cross multiplication and find an unknown value in two equal ratios.
Read guide →Fraction arithmetic, decimal-to-fraction conversion, ratios and proportions. The pages in this cluster are intentionally connected: calculator pages handle the arithmetic, while the guides answer informational searches, show worked examples and explain how to interpret the result.
Use the examples as reference points, then open a calculator and substitute your own values. For decisions involving contracts, taxes, health, payroll rules, construction requirements or other high-stakes details, verify the real-world assumptions with an appropriate authoritative source.
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