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Number Rack, by The Math Learning Center

Chrome Web Store listing by Clarity Innovations, Inc.

  • Trader

A Chrome extension with 100 000 users, a widely installed extension.

No site access is declared in the manifest, so it cannot read the pages you open on its own.

What the developer says, and 5 screenshots

Loading from the Chrome Web Store. Open the listing if it does not appear.

Users
100 000
Rating
5.0 (1 ratings)
Users, last 17 days
unchanged
Rating, last 30 days
Not watched long enough to say
Version
3.0.1
Updated in the store
2019-08-22
Published
2015-07-08
Manifest
V2
Browser access
4 permissions

How it has moved

Users
unchanged since 01.09
100k · 4 readings
  1. 2026-09-01100k
  2. 2026-09-02100k
  3. 2026-09-10100k
  4. 2026-09-17100k
Rating
unchanged since 01.09
reviewsrating 5.00 · 4 readings
  1. 2026-09-01reviews1rating5.00
  2. 2026-09-02reviews1rating5.00
  3. 2026-09-10reviews1rating5.00
  4. 2026-09-17reviews1rating5.00
Users
unchanged since 01.09
100k · 4 readings
  1. 2026-09-01100k
  2. 2026-09-02100k
  3. 2026-09-10100k
  4. 2026-09-17100k
Rating
unchanged since 01.09
reviewsrating 5.00 · 4 readings
  1. 2026-09-01reviews1rating5.00
  2. 2026-09-02reviews1rating5.00
  3. 2026-09-10reviews1rating5.00
  4. 2026-09-17reviews1rating5.00

A dot marks a day the store showed a different number. Between them the line carries the last one forward: we read every listing more than once a day and record a point only when something moves. History beyond ninety days is in the app.

What it can reach

No site access is declared in the manifest, so it cannot read the pages you open on its own.

  • Keep running while the browser is open background
  • Declares clipboard
  • Put data on your clipboard clipboardWrite
Show the remaining 1
  • Store data in your browser storage

The full permission history for this extension

What changed recently

Nothing has moved on this listing since we started watching it.

The publisher

Clarity Innovations, Inc. publishes 10 listings we track, 1.6M users between them. Listed website: mathlearningcenter.org.

  1. Number Pieces, by The Math Learning Center Clarity Innovations, Inc. · published 2015-07-08 200k users ★ 4.3
  2. Geoboard, by The Math Learning Center Clarity Innovations, Inc. · published 2015-07-08 200k users ★ 4.4
  3. Fractions, by The Math Learning Center Clarity Innovations, Inc. · published 2016-07-18 200k users ★ 3.0
Show 5 more from this publisher
  1. Number Frames, by The Math Learning Center Clarity Innovations, Inc. · published 2015-07-13 200k users ★ 5.0
  2. Pattern Shapes, by The Math Learning Center Clarity Innovations, Inc. · published 2015-07-09 200k users ★ 4.2
  3. Number Line, by The Math Learning Center Clarity Innovations, Inc. · published 2015-09-18 200k users (last published figure) ★ 4.6
  4. Money Pieces, by The Math Learning Center Clarity Innovations, Inc. · published 2016-01-21 100k users
  5. Math Vocab Cards, by The Math Learning Center Clarity Innovations, Inc. · published 2015-07-08 100k users (last published figure) ★ 2.0

Like this one

Listings the catalog judges closest in what they say they do.

  1. Number Frames, by The Math Learning Center Describes nearly the same job, with a large installed audience 200k users ★ 5.0
  2. Number Pieces, by The Math Learning Center Describes nearly the same job, with a large installed audience 200k users ★ 4.3
  3. Number Line, by The Math Learning Center Describes nearly the same job, with a large installed audience 200k users (last published figure) ★ 4.6
  4. Math Fun: Addition & Subtraction Describes a similar job, smaller audience 21 users
  5. Addition and Subtraction Describes a similar job, smaller audience 27 users

The top 5 only. The full comparison, with why each one is close, is on the alternatives page; ranking a whole neighbourhood by your own criteria is in the app.

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Figures come from our own daily pass over the public Chrome Web Store listing, last read on . We publish no contact details for extension developers.