Comparison

Grammar Ninja vs Osmo Numbers

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

Grammar Ninja

Engage in a word game where you identify grammatically correct sentences by targeting specific words with ninja stars. Hone your grammar skills to become a master word ninja.

Highlights
  • Target words in sentences
  • Identify grammatically correct sentences
  • Improve grammar skills
  • Word-based ninja game
Features
Read full description

Your mission is to throw ninja stars at words! These words are sneaky and have hidden themselves in grammatically correct sentences. Use your grammar skills to find your targets, and become the ultimate ninja master!

About

Osmo Numbers

Engage in hands-on math activities with physical tiles that interact with your device. Solve problems to collect virtual fish, learn geography, and explore marine biology in a fun, stress-free environment.

Highlights
  • Hands-on play with physical tiles
  • Counting, addition, subtraction, multiplication
  • Collect over 100 virtual fish
  • Learn geography and marine biology
  • Real-time feedback
  • Stress-free learning environment
Read full description

Dive into an ocean of hands-on math fun! In Osmo Genius Numbers, play with physical Osmo Numbers Tiles, including dots and digits. When your results match the numbers on the screen, cartoon bubbles burst with a satisfying pop! Count, add, subtract, or multiply to collect over 100 fish across the world to learn about geography and marine biology! Real-time feedback lets kids learn math through experimentation in a stress-free environment. When kids get the idea that there are multiple good ways to solve a problem, math becomes creative and fun. Play your favorite Osmo Genius Numbers on both iPhone and iPad! Use your iPhone with the Osmo Base for iPad and Genius game hardware - each can be found at playosmo.com. * Requires the Osmo Base and Osmo Numbers Tiles. Each sold separately or as part of Osmo Genius Starter Kit or Osmo Genius Numbers. * Other Osmo Genius Starter Kit games Masterpiece and Newton are not available on iPhone today, they will be released in the next month or two, so keep your eyes peeled! * Please see our device compatibility list here: https://support.playosmo.com/hc/articles/115010156067 * Compatible iPhones: iPhone 12, 12 Pro, 12 Pro Max iPhone 13, 13 Pro, 13 Pro Max iPhone 14, 14 Plus * Not compatible: iPhone 14 Pro, 14 Pro Max iPhone 12 Mini,13 Mini iPhone SE (1-3) iPhone 11 Series and older “One of 2016’s most intuitive product designs.” - Fast Company Award "...once again, Osmo has built something wonderfully creative and interactive." - Venture Beat "Osmo Numbers takes the fear out of figures." - Forbes "…revamp the unimaginative worksheets educators use to teach math" - TechCrunch Winner of the toy industry's top awards: **Best Design** - Good Design, 2016 **Best Product Designs** - Fast Company Finalist, 2016 **Innovative Toy of the Year** - TOTY Finalist, 2015 **Best Inventions** - TIME, 2014 About Osmo Osmo is using the screen to create a new healthy, hands-on learning experience that promotes creativity, problem-solving and social interaction. We do this with our reflective artificial intelligent technology.

Screenshots

Grammar Ninja4 screens
Osmo Numbers4 screens

Verdict

The call

The clearest difference is review sentiment: Grammar Ninja at 100% against Osmo Numbers's 33%. Grammar Ninja also leads on rating (5.0 vs 3.8) and iOS requirement (13.0 vs 15.0). Osmo Numbers's advantage is in-app purchases (none vs 6) and ads (none vs shown). On price, ratings volume, monetization model and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Grammar Ninja sells 6 one-off in-app purchases. Osmo Numbers asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Grammar Ninja holds the better App Store score, 5.0 against 3.8. Both are backed by a comparable volume of ratings — 52 and 146 respectively. Written reviews point the same way: 100% of Grammar Ninja's written reviews are positive against 33% of Osmo Numbers's.

UpkeepUpdate frequency

Grammar Ninja ships an update every 8 months, Osmo Numbers every 2 months. The most recent releases landed on October 26, 2026 and October 24, 2026 respectively.

Scorecard6 real differences · 4 level
Grammar Ninja versus Osmo Numbers: the parameters behind the verdict, then further details
ParameterGrammar NinjaOsmo Numbers
PriceFreeFree
Rating5.0 (52 ratings) — better3.8 (146 ratings)
Positive reviews100.0% of reviews — better33.3% of reviews
Number of ratings52146 — better
Update frequencyEvery 8 monthsEvery 2 months — better
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13.0 — better15.0
Further details — not scored
Size179 MB358 MB
Age rating12+4+
DeveloperGreg LiebermanTangible Play

Customer experience

Grammar Ninja

All ratings52 ratings
Positive98.1%
Neutral1.9%
Negative0.0%
Written reviews36 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Osmo Numbers

All ratings145 ratings
Positive66.2%
Neutral9.0%
Negative24.8%
Written reviews30 reviews
Positive33.3%
Neutral10.0%
Negative56.7%

User reviews

Grammar Ninja

From 52 App Store ratings

What we love

  • 👍 Fun and engaging gameplay
  • 💡 Educational and improves grammar
  • 🚀 Great for all ages
  • ✨ Visually appealing graphics
  • ✅ Easy to use and understand

Room to improve

  • ↔️ Limited side-to-side movement on iPad

Osmo Numbers

From 146 App Store ratings

What we love

  • 👍 Great way to practice math
  • 👍 Kids enjoy it
  • 👍 Fun concept
  • 👍 Cute graphics and interactive things
  • 👍 Hands-on learning

Room to improve

  • 🐛 App glitches frequently
  • 🐛 App crashes
  • 🐛 Game doesn't register tiles
  • 🐛 Not compatible with certain iPads
  • 🐛 Codes not working

Bugs and requests

Grammar Ninja

Requested features

1 request
  • Side-to-side movement for iPad

Osmo Numbers

Reported bugs

12 issues
  • App glitches
  • App crashes
  • Game will not register tiles
  • Reflector not sensing tiles
  • App won't open on old iPads
Show 7 more
  • Unable to login or create new account
  • Codes to create account not working
  • Not compatible with iPad Pro 4th generation
  • App crashes when trying to open
  • Black screen when starting app
  • Numbers go up to 35 then lay down for 14
  • Update caused son to stop playing

Requested features

5 requests
  • Increase timer duration
  • Add more drawing games
  • Add voice reading for math problems
  • Improve tile sensing accuracy
  • Make game go slower

In-app purchases

6 purchases

Grammar Ninja

One-time6
  • 100 Diamonds$0.99
  • 550 Diamonds$4.99
  • 1200 Diamonds$9.99
Show 3 more
  • 2500 Diamonds$19.99
  • 5200 Diamonds$39.99
  • 15000 Diamonds$99.99
None

Osmo Numbers

No in-app purchases

Questions

Is Grammar Ninja free?
Grammar Ninja is free to download, with in-app purchases available.
Is Osmo Numbers free?
Osmo Numbers is free to download, with no in-app purchases.
Which has better reviews, Grammar Ninja or Osmo Numbers?
Grammar Ninja is rated higher. Grammar Ninja averages 5.0 out of 5 from 52 ratings, while Osmo Numbers averages 3.8 from 146 ratings.
Do Grammar Ninja or Osmo Numbers have ads?
Grammar Ninja shows ads; Osmo Numbers does not.
Which is updated more often, Grammar Ninja or Osmo Numbers?
Grammar Ninja ships an update every 8 months, and Osmo Numbers every 2 months. Most recently, Grammar Ninja was updated on October 26, 2026 and Osmo Numbers on October 24, 2026.

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