Overview
An answer key tells you the answer is wrong. Maths Check tells you where: it checks every line of your working against the line before it, and points at the first one that doesn't follow — “Your working went wrong at line 2: −(2x − 5) became −2x − 5; the minus sign must multiply both terms, giving −2x + 5.”
Checking your working
- Photo — take a photo of one problem's working, lines in order. Handwriting is fine. If the question is on the page, it is read too.
- Type it — the problem (optional), then your working, one step per line. Plain typing works:
2x^2 - 5x + 3 = 0,x = 3/2 or 1.
Press Check every line.
Reading the result
- ✓ beside a line — it says the same thing as the line before.
- ✗ — the first line that doesn't follow, with what went wrong and a one-line habit to stop it happening again.
- – — a line that isn't maths the engine checks (words, an inequality). It is skipped, never marked wrong.
A final line of answers (x = 2 or x = 3) is substituted back into the equation, and a missing answer is named: “Missing x = −3.”
How it decides
The verdict comes from a maths engine, not from AI judgement. It tests each line against the one before at a dozen different values of x: two expressions that give the same number every time are the same; if they differ anywhere, the step is wrong. Equations are compared by their solutions. Only after the engine has found the wrong line does AI describe the slip in words.
What it can and can't check
| Checks | Doesn't check |
|---|---|
| Algebra and simplifying · expanding and factorising · linear and quadratic equations · fractions, powers, roots · logarithms · trigonometric identities · numeric answers | Geometry proofs and constructions · inequalities · steps written only in words · anything needing a diagram |
Where slips go
- Each slip is saved to your Error Book (as Maths Check) with its cause — a careless slip, a concept gap, or a wrong formula.
- It also counts in your Learning Genome's thinking profile: a sign or arithmetic slip counts against precision, a bracket or power mistake against algebraic manipulation, a dropped step against procedure. A working that checks out all the way through counts in your favour.
- Your recent checks show on the right, with where your slips cluster.
Checked doubt answers
When you ask a maths question in the Doubt Scanner, the final answer is checked by the same engine — roots are put back into the equation, derivatives are worked out again, integrals are differentiated back. A note under the answer tells you how it went:
- Checked by the maths engine — the result was verified independently.
- Checked — the first attempt had an error — the engine caught a mistake, the question was solved again, and this answer passes.
- Not verified — the engine found a problem it couldn't resolve. Check the answer carefully.
Answers that aren't checkable maths (a history answer, a geometry proof) show no note.
Graphs
Graph a function on the right: type y = x^2 - 5x + 6, set the range of x, and press Draw. The roots are marked in red. A doubt that asks you to draw or sketch a graph gets the graph in its answer too.
Tips and limits
- One problem per photo, in good light, lines in order.
- Write one step per line — two steps crammed on one line are checked as one.
- 30 photo checks and 120 typed checks a day.
- Photos are read by our AI provider. For students under 18 this needs a parent's consent for AI help — see Data protection.