At home
Parents and carers. When homework stalls on a word rather than a calculation, look it up together. You do not need to remember the maths yourself — the explanation is written for both of you.
Free · Open · No sign-in
Math Word Explorer
Word problems are often hard for a reason that has nothing to do with the maths. They are full of words like denominator, perimeter and regroup. This tool explains all 267 of those words, from Kindergarten to Grade 5, in plain language a child can read on their own.
Open the Explorer
Works on a phone, tablet, laptop, or any browser. Nothing to install.
Note: turn up the volume — sound effects help guide the way.
Why we made it
A child can know how to subtract and still be stuck on a problem, simply because they are not sure what how many are left is asking. The maths was never the barrier. The language was.
So every word here is written twice over. First as a short, plain definition. Then as a small story with a real situation — someone counting grapes, fencing a garden, sharing a pizza — because a word makes far more sense when you can picture it happening.
Every explanation is checked against the Flesch reading scale when the site is built, so the language stays within reach of the age it is written for instead of drifting upward over time.
What is inside
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Plain definitions
Every word said simply, in one or two short sentences.
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A worked example
A short story that shows the word doing its job in a real problem.
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Common mix-ups
The mistake children usually make with this word, named plainly.
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Read aloud
A button that speaks the word and its meaning for children still building reading fluency.
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A map of the words
A 3D map showing how each word sits inside its grade and its topic.
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Search everything
Look up any word across all six grades at once, by name or by meaning.
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A companion cat
A small pixel cat keeps your company, offering quiet encouragement and occasional tool tips. It never interrupts, and it can be turned off entirely.
Who it is for
In the classroom
Teachers. Put it on the board when a new word comes up, or let children look words up themselves during independent work. Words are grouped by grade and topic and cited to their standard — Common Core by default, with the UK National Curriculum and India's NCERT a tap away — so it lines up with what you are already teaching, wherever you teach it.
In tutoring
Tutors and support staff. Check quickly whether a child is stuck on the vocabulary or the method, and use the shared examples as a starting point for talking a problem through.
On their own
Children. Big buttons, read-aloud, and a tick beside every word already explored. Nothing to sign up for and no wrong turns to take.
Meet the team
The Math Word Explorer was developed by researchers from the Society and AI Research Group, University of Massachusetts Amherst, and Harvard University.
Aubrey Coyne
Master's Degree Student
Sharon Edwards, Ed.D.
Clinical Faculty
Sai Gattupalli, Ph.D.
Learning Systems Designer
Robert Maloy, Ed.D.
Senior Lecturer
No personal data. Ever.
This site collects no personal information — there is no sign-in, no advertising, and nothing about you or a child is stored on any server. The only things saved are on your own device, in your browser: which words have been opened, and whether sound is on.
We do use Google Analytics to count anonymous website traffic — how many visits the site gets and whether they arrive on a phone, a tablet, or a computer — so we can keep the Explorer fast and comfortable on the devices learners actually use. It reports traffic numbers only: nothing personal, nothing that identifies anyone, and nothing about which words a child reads.
Free to use and to build on
Made by the Usable Math team at the University of Massachusetts Amherst, with the Society & AI research group. Every part of this tool — the word bank, the readability checks and the code — is public, so educators can see exactly how it was built, reuse it, or adapt it for their own district: github.com/sai-educ/math-vocab.
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Licence — CC BY-NC 4.0
The Math Word Explorer is an Open Educational Resource under the Creative Commons Attribution-NonCommercial 4.0 International licence. You are free to share and adapt it for non-commercial purposes, as long as you give appropriate credit.
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3D assets
The knowledge graph's centre is "Sun" by SebastianSosnowski, licensed under the CC Attribution 4.0 licence.
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Pixel cat
The Explorer's pixel-cat companion uses a sprite sheet from KINGS-MZ/PixelCat by Imad El Khaider, under the MIT licence. Only the artwork is reused; the coaching it does is ours.