➗ Math apps and platforms
Open Middle
By Robert Kaplinsky and contributing teachers. Visit Open Middle
Desk research from the maker's own pages. Not yet tried by us. Checked 2026-10-24.
Open Middle is a free website of more than 700 math puzzles for kindergarten through high school, sorted by grade and Common Core standard. A typical problem asks a child to place the digits 1 to 9 in boxes to make the largest product or a sum closest to one, so there are many ways in but one best answer. Each problem page shows a hint and the answer. Teachers can embed problems in Google Classroom or Canvas, and some now work as interactive on-screen versions.
Our take: Great for parents and teachers who want a few rich problems a week; to avoid peeking, give children the problem without the answer.
Checked in a browser
A browser check on 2026-10-25: what loads, the ads and trackers we saw, and what a child meets first. Not a hands-on test.
| Child safety: 4 out of 5 | No ads or chat; links out to Amazon (books), Redbubble (stickers) and paid workshops. |
|---|---|
| Data: 4 out of 5 | Only Google Analytics and Tag Manager loaded, plus a Leadpages email pop-up service. |
| Ease: 3 out of 5 | Long lists of text links to problems and worksheets, written for teachers. |
| Cost honesty: 4 out of 5 | Problems are free; the page also sells a book, stickers and an online workshop. |
What we found
- Contacted 9 outside sites; the only known analytics were Google Analytics and Tag Manager.
- A Leadpages email-capture box loaded in a frame.
- Page text: 'TAKE THE ONLINE WORKSHOP' and 'LOOKING FOR AN OPEN MIDDLE BOOK?'.
- Links out to amzn.to and redbubble.com.
From the test: Free, ad-free challenging math problems for teachers and parents to use with children.
| Ages it suits | grades K-12 (about 5-18) |
|---|---|
| What its terms say about age | Not stated; the site has no terms of use or account sign-up that we could find. (terms) |
| Price | Free. Free (Oct 2026); a paid book, stickers and a paid online workshop for teachers are linked from the site. |
| Works on | Web |
| Account | No account needed |
| Ads | None |
| In-app purchases | None |
| The AI in it | No AI. |
What's good
- Free with no sign-up
- Short, deep problems for every grade
- Teachers can embed and hide hints or answers
- Printable worksheets in three languages
Watch for
- Answers sit one click away on each problem page
- No privacy policy or terms found
- Not a full course; problems stand alone
- Links out to Amazon for the book
Data and privacy
Not stated; we found no privacy policy on the site. The pages load Google's analytics tag. Read the privacy policy.
Does it work?
The maker's own claims only; no independent study was found.
In the Big Index
Alternatives to Open Middle
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99math
99math (Estonia) · ages about 5-14 (grades K-8)
A low-effort, free way for teachers to make fact practice lively; parents of kids who dislike timed competition may want a calmer tool.
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ABCmouse
Age of Learning, Inc. · ages about 2-6 (preschool to kindergarten)
A full preschool program for families who want one paid app; cancel carefully and watch the reward loop.
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ABCya
ABCya.com LLC (a division of IXL Learning) · ages about 4-12 (pre-K to grade 6+)
Handy for quick grade-level practice in class or at home; skip if you want an ad-free experience without paying.
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Adventure Academy
Age of Learning, Inc. · ages grades 3-8 (about 8-13)
Good for kids who love online games and need a nudge toward school subjects; families wanting no social contact should set chat to off or choose a solo app.
Desk researchPaidNo ads
ALEKS
McGraw Hill (ALEKS Corporation) · ages school-age students through college (K-12 and higher ed courses)
A rigorous, mastery-based option for motivated older students or homeschoolers; younger or easily bored kids may prefer something more playful.
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AoPS Online
Art of Problem Solving (AoPS Incorporated) · ages grades 5-12 (about 10-18)
A strong fit for a child who loves hard math and wants contest prep; a child who is behind in math needs something gentler.
Where these facts come from
- https://www.openmiddle.com/
- https://www.openmiddle.com/a-new-way-to-use-open-middle-interactive-problems/
- https://www.openmiddle.com/adding-decimals-to-make-them-as-close-to-one-as-possible/
Prices, terms and features change. Nobody paid to be listed, nothing here is an affiliate link, and Peabody never rates itself. Where we and the maker disagree, the maker's own pages are the ones to trust.