Guides
Practical math how-tos, no fluff.
Clear, step-by-step guides to the maths people actually look up: adding fractions, calculating a percentage, simplifying a ratio, mean median and mode, and more. Each one is backed by a free calculator that runs entirely in your browser.
How to Add Fractions (and Subtract Them)
Add fractions with a common denominator, then simplify. Worked examples plus subtraction and mixed numbers.
Read guideHow to Calculate a Percentage (Three Ways)
Divide by 100 and multiply, or divide one number by another and multiply by 100. Here are the three percentage questions, each worked out.
Read guideHow to Find the LCM and GCD of Numbers
Use Euclid's method for the GCD, then LCM = a × b ÷ GCD. Here is each step, worked out for two numbers and a longer list.
Read guideHow to Find the Mean, Median and Mode
Add and divide for the mean, sort and take the middle for the median, count for the mode. Here is each one, worked out.
Read guideHow to Simplify a Ratio to Lowest Terms
Divide both sides by their greatest common divisor. Here is the method, with decimals and solving a proportion covered too.
Read guideHow to Solve a Quadratic Equation
Use the quadratic formula and read the discriminant. Here is the method, with the real, repeated and complex cases worked out.
Read guideOrder of Operations (PEMDAS) Explained
Brackets first, then exponents, then multiply and divide, then add and subtract. Here is the rule, with worked examples and the usual traps.
Read guideSkip the reading — just use the tools
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