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Math

The Math calculators handle the everyday arithmetic that school taught once and everyone forgets under pressure: percentages and percentage change, averages with the median shown alongside, ratio simplification and scaling, and fraction arithmetic that reduces the result to lowest terms.

Each tool shows the rule behind the answer and a worked example, so you can re-derive the result on paper — or just trust the calculator and move on.

Percentage Calculator Three percentage calculations in one: find X% of Y, find what percent X is of Y, and find the whole when X is Y% of it. Percentage Change Calculator Calculate percentage increase or decrease between two values, with the absolute change and multiplier. Average Calculator Calculate the mean, median, sum and count of any list of numbers. Ratio Calculator Simplify any ratio to its lowest terms, see each share as a percentage, and split a total according to the ratio. Fraction Calculator Add, subtract, multiply and divide fractions with automatic simplification to lowest terms, plus decimal and percentage equivalents.

Frequently asked questions

How do I calculate a percentage of a number?

Convert the percentage to a decimal and multiply: 35% of 80 = 0.35 × 80 = 28. The Percentage Calculator handles “X% of Y”, “X is what % of Y” and reverse percentages.

Why is a 25% increase not undone by a 25% decrease?

Because the base changes: +25% from 80 reaches 100, but −25% from 100 falls to 75. The Percentage Change Calculator shows the multiplier and the reverse operation.

When should I use the median instead of the mean?

Whenever the data has extreme values or a skewed distribution — incomes, house prices, response times. The Average Calculator shows both so the difference is visible.

How do I simplify a ratio?

Divide both terms by their greatest common divisor: 24:36 → divide by 12 → 2:3. The Ratio Calculator also splits a total amount in the given proportion.

How do I add fractions with different denominators?

Find a common denominator (multiplying the two always works), convert both fractions, then add the numerators. The Fraction Calculator simplifies the result automatically.