About Longhand

Longhand is a set of free maths calculators built around one rule: the answer is never shown without the working. It is made for students checking homework, parents helping with it, and anyone who wants to see why a number comes out the way it does. There is no sign-up and no login.

The site is written and maintained by Shaheer Bin Ramzan, a software engineer and SEO specialist based in Pakistan.

How we check the maths

Every calculator uses a standard formula from textbook mathematics. Before publishing, each one is tested against hand-worked examples, including zero, negative numbers, repeated roots and invalid inputs. Results are rounded only at the end, to 12 significant digits. If you find an error, tell us and we will correct it and update the page.

Formula sources

• Fractions and percentages: OpenStax, Prealgebra (openstax.org).
• Linear equations in one variable: OpenStax, College Algebra.
• Quadratic formula and discriminant: OpenStax, College Algebra.
• Mean, median, mode, range, variance and standard deviation: OpenStax, Introductory Statistics.
• GCF and the Euclidean algorithm: Euclid, Elements, Book VII, Proposition 2.
• Slope, distance, midpoint and line equation: OpenStax, College Algebra; the distance formula follows from the Pythagorean theorem.
• Pythagorean theorem: Euclid, Elements, Book I, Proposition 47.

Why only a few calculators

We add a calculator only when we can verify it and explain it properly. A short list that is right beats a long list that is not.