Type the problem. The big box on the home page, and the search box in the bar at the top of
every page, take any problem — 47 + 38, 3/4 ÷ 1/2, solve 3x + 2 = 11,
area of a circle with radius 5, or a whole story problem — and open the helper that works it out.
Or take a photo of it. The camera button beside the problem box reads a printed problem from a photo, a picture or a pasted
screenshot, on your own device, and puts it in the box for you to check before it's worked out.
Or pick a topic from Browse all topics (with buttons for each grade band), or from the bar
of helpers at the top of every page.
Want the idea explained first? The lessons walk through how to do each kind of problem,
with a worked example and links to try your own.
Each helper covers one topic and shows the work the way it's done on paper: one step at a time, with the reason for each
step and a picture or diagram beside it, then the answer and a check that it makes sense.
On every helper
Four ways to work, in the buttons above the steps:
Show all work — every step at once.
One step at a time — try each step yourself, then reveal it (←→).
Check my answer — type your answer and get told if it's right. It knows 3/4, 0.75 and 75% are the same, and spots
common mistakes ("you added the denominators").
Tutor me — before each step it asks what you'd do next, with a few choices and a hint after a wrong pick, then gives a score.
Also on every page:
Copy link saves the exact problem: send it to a friend, a student or yourself. The QR code button (Q)
opens it on a phone.
Read aloud (R) reads the steps; Voice picks the voice and speed.
Math keys (K) — a row of buttons for ÷ × − √ π ² and fractions. On phones they come up by themselves.
Make a problem for me makes a new practice problem of the kind you pick (N for the next one).
Light and dark (D), bigger or smaller text (+−), and big screen for a projector (B).
Recent brings back problems you worked on, and each page opens where you left it.
Photo of the problem — the camera button reads a printed problem from a photo or screenshot. It works best on clear,
printed text; handwriting often can't be read yet. The picture never leaves your device (the reading engine, about 7 MB, is
downloaded once, the first time).
Common Core — under the heading, the standards the open tab practices; hover a code to read it, click it for the
Standards page. The matching is ours, not official.
Add to assignment — collects the problem on the screen, exactly as it is, for an assignment (see below).
Report a problem — if an answer is wrong or a step is confusing, this opens a short form with the problem's link already filled in.
Press ? on any page for the full list of keys, and / to jump to the problem box.
Pages print cleanly, and once you've visited, the site works offline. On a phone you can add it to your home screen
(in Safari: Share → Add to Home Screen; in Chrome: the menu → Install app).
Typing a problem
Ordinary wording is fine. "please solve 47+38", "what is forty-seven plus thirty-eight?", "simplify 18/24 step by step",
"Problem 4: find the GCF of 12 and 18" — the helpers skip the extra words and read numbers written as words.
Signs: + − × ÷ or */x between numbers. Powers with ^ (2^5, x^2),
roots with sqrt or √, fractions as 3/4, mixed numbers as 2 3/4, percents with %.
One problem at a time. A numbered homework list ("1. Write an equation … 2. How many …") is fine in a story problem:
the question numbers are skipped.
If a page can't read it, it says so instead of guessing, and usually says why or links to the helper that does that
kind of problem. You can also fill in the boxes yourself, or pick the kind of problem.
Still stuck? Tell us what you typed — that's how the helpers learn
new wording.
The helpers
What each helper does, problems you can type into it (click one to try it), and what it can't do yet.
The Area BoxMultiplying out, factoring, solving quadratics, vertex form, polynomial division, and adding or subtracting polynomials
The Complex PlaneImaginary and complex numbers: powers of i, arithmetic, the plane, polar form, De Moivre's roots and powers, and quadratics with complex answers
The Counting TreeCounting: multiply the choices, arrangements (nPr), combinations (nCr), handshakes, diagonals and factorials
What it does
Multiply the choices: outfits, menus, coins and dice, quizzes, PINs, codes and license plates (with or without repeats)
Order matters: nPr, officers and places, lining up, the letters of a word (repeated letters too), around a table or a bracelet
Choosing groups: nCr, from two groups (exactly, at least, at most, none, all, one of each), up to k (sums of C(n, r)), repeats allowed (stars and bars)
Handshakes (also before and after, and with n people), games, cards sent, diagonals, lines and triangles through points
Factorials and formulas (n!, n!/k!, C·C), and probability by counting for a group chosen at random or a lottery
The Graph PaperPlotting points, tables of values, graphing functions, solving systems by graphing, graphing inequalities, moving shapes, and scatter plots
The Scratch PaperA practice sheet where you do the work yourself: column adding, subtracting, multiplying and dividing, or line-by-line algebra, with checking as you go
What it does
Add
Subtract
Multiply
Divide
Line by line (expressions, equations, inequalities, systems, word problems)
A story with no question (it usually ends with a ?)
A question that doesn't ask for an amount, like "What is the weather?"
A story whose kind it can't tell: it asks you to pick the kind and fills in the numbers
Counting problems (ways, handshakes, arrangements): no helper does these yet
Probability stories go to the Chance Spinner, normal-curve stories to the Bell Curve, biggest-or-smallest (optimization) stories to the Rate Machine, and sequence stories to the Number Staircase
Two speeds written together (“at 60 and 40 miles an hour”) — give each its own sentence
No helper matches that. Try a simpler word, or type the whole problem into the box on the home page.
Story problems
Paste a whole word problem into The Story Problem. It works out what kind of
story it is, shows what it understood under What the story says (fix anything it got wrong there), and works it out
in the same steps every time: read it, say what's asked, list what you know, choose the operation (or write an equation),
draw it, solve, and answer in a sentence with a check.
Grades K–5: adding to and taking from, putting together, comparing, equal groups, arrays and area, times as many,
rates and unit prices, money and change, elapsed time, fractions of an amount, percents and discounts, two-step stories,
and remainders that matter (vans needed, full boxes, leftovers).
Algebra: number puzzles, consecutive numbers, ages, perimeter and angles, two plans that cost the same, tickets and coins,
distance-rate-time (opposite ways, toward each other, catching up, wind and current), working together, mixtures, interest,
a fixed fee plus so much each, at most / at least, proportions, prices that change, groups tied together
("10 more adult tickets than children's"), and dozens more shapes of equation.
When the problem asks you to write an equation or expressions, the answer shows them too, along with the solution.
Some problems belong on another helper — probability, the normal curve, optimization, three equations — and the page
says so and opens the right one with the problem filled in.
Tips: include the question sentence ("How many …?"); write numbers as digits when you can; if it picks the wrong kind,
use Not right? Change it.
Printable worksheets on any topic, with an answer key and a QR code to check answers. Up to four versions (A–D) with different numbers, and a link that reopens the same worksheet.
The Common Core standards, each with the helpers that practice it (an unofficial match).
Making an assignment (no accounts)
On any helper, set up a problem (type it, or press New problem) and press Add to assignment beside Copy link. Do that for every problem you want, on any helpers.
Open the assignment builder (the "in your assignment" link beside the button). Put the problems in order, remove any, or preview one as students will see it.
Give it a title, instructions and a due date. Choose whether students see the steps after answering, and whether they get more than one try.
Press Share: make the link, then copy the link, show the QR code, or copy the ready-made text for Google Classroom or email.
Students open the link, type their name and work the problems. At the end they copy a result line and send it to you.
Paste everyone's lines into Class results: right or wrong on every problem, how many tries each took, and who handed in late.
The whole assignment is in the link, so links you've shared keep working; the draft you're building is kept only in this browser.
Worksheet versions
In the Worksheet Maker, pick Versions: 2, 3 or 4. Each version (A–D) has the same kinds of problems in the same order with different numbers, its letter in the header, and its own answer key (all keys at the end, or after each version). Shuffle the order in B–D also mixes the order within each section. Worksheet link gives a link and QR code that reopen the same worksheet, with the same numbers in every version.
Not yet: math we're still working on
The site doesn't do everything yet. These are known gaps — if one of them matters to you, say so; requests decide what comes next.
Counting with conditions — people who must sit together, codes with rules like "even numbers only", paths on a grid,
identical things into boxes. The Counting Tree does plain counting, arrangements and combinations, and says when a condition is beyond it.
Handwriting in photos — the camera button reads printed problems; handwritten ones usually can't be read yet.
Optimizing with constraints — linear programming (the most profit from several limits). The Graph Paper shades the
region, but doesn't yet find the best corner for you.
Calculus word problems — "what size box has the biggest volume" has to be set up as a function first; the Rate Machine
then finds the maximum.
Binomial probability typed into The Bell Curve as a story — The Story Problem works it out; the Bell Curve needs the numbers in its boxes.
Geometry: Heron's formula for a triangle from three sides, and naming sides by their corners (AB, BC).
Algebra: literal equations (solve for r), compound inequalities, and systems in letters other than x and y on the Balance Scale.
Calculus: integration by parts and other advanced integrals.
Proofs, constructions with a compass and ruler, and anything beyond a first-year college course.
Other languages — the site reads and writes English only for now.
Each helper's own "Not yet" list (above, under The helpers) has the details for that topic.
Questions
Is it free? Yes — no accounts, no sign-up, no ads. See About.
Does it keep what I type? No. Every problem is worked out in your own browser; your settings and progress are saved only on
your device. See Privacy.
Can I trust the answers? Every answer is worked with exact numbers and checked a second way, and the site runs a
self-test of more than 22,000 checks before anything changes. If you find a wrong one,
use Report a problem on that page.
Does it work on a phone or tablet? Yes, in any modern browser — and offline once you've visited.