About Math Lantern
Math Lantern is a set of free math calculators that show their working. Enter an expression, a fraction or a set of numbers and the page gives the answer together with every step, so you can follow the reasoning, copy it into your notes or check your own homework against it.
Why show the steps
An answer on its own teaches little and cannot be checked. A worked solution can. Each Math Lantern calculator runs real JavaScript in your browser and prints the intermediate lines: the factors tried, the formula used, the arithmetic after substitution.
What we do not do
- We do not sell answers or take tests for anyone. The tools explain; the work stays yours.
- We do not rank or grade students.
- We do not use data about your problems: what you type never leaves your browser.
How the calculators were checked
The Math Lantern team writes each calculator and its explanation. On 12 October 2026 we drove the live solvers with 150 random problems each, 750 in all: GCF and LCM, proportion, quadratic formula, Pythagorean theorem, and mean with standard deviation. Every answer, and every value shown in the working, matched an independent calculation. The binomial calculator was tested on another 140 random cases, with n up to 1,000, against exact integer arithmetic; the largest difference was 0.0000005, below the six decimals shown.
A page’s “updated” date changes only when its content does.
Contact and privacy
Corrections and requests for new calculators go to the address on the contact page. The privacy policy lists what little the site stores and the terms of use set the ground rules.
Frequently asked questions
Who writes Math Lantern?
The Math Lantern editorial team. We rely on standard definitions and worked examples rather than personal credentials.
Is it free?
Yes. There is no sign-up and there are no ads at the moment.
May I use it for homework?
Use it to understand and check your work. If your teacher forbids calculators, follow that rule.
Back to the Factoring Calculator on the home page.