Comparison

R21 vs Math Cats

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

Head to head
About

R21

Features
Read full description

R21 is a new six-level reading series carefully designed to help young learners develop the skills they’ll need to succeed in the 21st century. Each book covers a range of topics and makes use of the latest Content and Language Integrated Learning (CLIL) methods to ensure they’ll appeal to young children and have a connection to children’s wider studies and experiences. With R21, reading is fun, inspiring as well as informative, and children will not only develop their reading competence but also become a great thinker in the 21st century.

About

Math Cats

This app offers interactive math practice for grades 1-6, rewarding children with collectible cat images and videos as they master arithmetic skills. It provides detailed progress tracking for parents and a virtual scratchpad for calculations, eliminating the need for paper.

Highlights
  • Grade 1-6 arithmetic practice
  • Collectible cat images and videos
  • Progress tracking and statistics
  • Virtual scribble pad for calculations
  • Identification of areas of struggle
Features
Read full description

Math Cats is a math app that rewards your kids with adorable cat images and videos as they practice and progress through Grade 1–6 arithmetic. For parents: - Say goodbye to grading your child’s answers in workbooks! - Progressive exercises for Grades 1–6 arithmetic are all included; never buy that “next grade” workbook again! - Scribbles for incorrect answers are recorded, helping you identify where and why they are struggling. - Track their overall progress and performance with statistics such as overall percentage score, time taken per quest, and time spent per question. Your kids will: - Practice Grade 1–6 arithmetic that becomes progressively more challenging, including addition, subtraction, multiplication, division, decimals, and fractions. - Unlock cute and adorable cats every time they pass a quest — try to collect them all! - Use the built-in virtual scribble pad for calculations; no paper or pencil needed! - No longer be able to peek at the answers in the back of workbooks! Download Math Cats today and help your child become a math wizard!

Screenshots

R213 screens
Math Cats4 screens

Verdict

The call

The clearest difference is price: R21 at Free against Math Cats's $5.99. R21 also leads on iOS requirement (9.0 vs 15.6). Math Cats's advantage is update cadence (every 5 days vs every 3 months). On ads, in-app purchases 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

R21 is free to download; Math Cats costs $5.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

R21 ships an update every 3 months, Math Cats every 5 days. The most recent releases landed on October 10, 2026 and September 26, 2026 respectively.

Scorecard3 real differences · 7 level
R21 versus Math Cats: the parameters behind the verdict, then further details
ParameterR21Math Cats
PriceFree — better$5.99
Rating—5.0 (3 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings—3 — better
Update frequencyEvery 3 monthsEvery 5 days — better
AdsNoNo
In-app purchasesNoNo
Monetization—Paid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS9.0 — better15.6
Further details — not scored
Size114 MB170 MB
Age rating4+4+
DeveloperCAVES BOOKS LTD.Knowledge Vortex, LLC

In-app purchases

None

R21

No in-app purchases

None

Math Cats

No in-app purchases

Questions

Is R21 free?
R21 is free to download, with no in-app purchases.
Is Math Cats free?
Math Cats costs $5.99, with no in-app purchases.
Do R21 or Math Cats have ads?
Neither R21 nor Math Cats shows ads.
Which is updated more often, R21 or Math Cats?
R21 ships an update every 3 months, and Math Cats every 5 days. Most recently, R21 was updated on October 10, 2026 and Math Cats on September 26, 2026.

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