Comparison

Duck Duck Moose Reading HD vs FLEX

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

Head to head
About

Duck Duck Moose Reading HD

This app offers a zoo-themed adventure to teach phonics and reading skills to young children. It features word and letter activities aligned with Common Core State Standards, along with a parent reporting tool to track progress. Developed with educators, it's designed for ages 3-7.

Highlights
  • Zoo-themed learning adventure
  • Phonics and reading skill development
  • Word and letter activities
  • Common Core State Standards alignment
  • Parent progress reporting tool
  • Developed with educators
Read full description

An award-winning app based on Common Core State Standards, Duck Duck Moose Reading teaches phonics and reading skills in a fun zoo-themed adventure. With word and letter activities, kids learn by playing with flamingos, monkeys, lions and more. Keep track of progress through a new parent reporting tool. AWARDS: Parents’ Choice Gold Award; Children’s Technology Review Editor’s Choice Award. AGES: 3-7. PLAY CATEGORY: Early Learning/Curriculum ACTIVITIES 9 ACTIVITIES BASED ON COMMON CORE STANDARDS 
 - Letter-sound and word activities 
 - Recognizing and naming lowercase letters 
 - Demonstrating knowledge of letter-sound correspondences 
 - Isolating and pronouncing sounds in CVC (consonant-vowel-consonant) words WORDS & LETTERS: Teaches phonics through 9 different activities - Learn the letter sounds for all consonants, short vowels and long vowels - Practice spelling consonant-vowel-consonant (CVC) words PARENT REPORTING: Includes a new reporting tool so parents and teachers can see how a child is progressing DEVELOPED WITH EDUCATORS: - Developed in conjunction with Stanford University Educator, Jennifer DiBrienza, PhD in - Early Elementary Education and former NYC public school teacher (K-Grade 2) - Tested extensively in Kindergarten classrooms COMMON CORE STANDARDS: RF.K.1d, RF.K.2d, RF.K.2e, RF.K.3a, RF.K.3b ABOUT DUCK DUCK MOOSE (A wholly-owned subsidiary of Khan Academy) Duck Duck Moose, an award-winning creator of educational mobile apps for families, is a passionate team of engineers, artists, designers, and educators. Founded in 2008, the company has created 21 top-selling titles and has received 21 Parents’ Choice Awards, 18 Children’s Technology Review Awards, 12 Tech with Kids’ Best Pick App Awards, and a KAPi award for “Best Children’s App” at the International Consumer Electronics Show. Khan Academy is a nonprofit with a mission to provide a world-class education for anyone, anywhere. Duck Duck Moose is now part of the Khan Academy family. We rely on our community of volunteers and donors. Get involved today at www.duckduckmoose.com/about. Check out the Khan Academy app to learn and practice all kinds of topics for elementary school through college and beyond. We’d love to hear from you! Visit us at www.duckduckmoose.com or drop us a line at support@duckduckmoose.com.

About

FLEX

This interactive educational tool helps teachers visualize basic math concepts like fractions and number lines. It allows for the creation of independent student projects and supplements math training programs. Enhance understanding of mathematical skills with various visual aids.

Highlights
  • Number lines visualization
  • Fraction tools
  • Number bonds
  • Number blocks
  • Create student projects
  • Mathematical symbols
Features
Read full description

FLEX - Math Tools is an interactive tool for teaching basic mathematics. It contains several different tools to enhance the understanding of mathematical concepts. With FLEX - Math Tools, you as a teacher visualize new mathematical concepts with your students using for example number bonds, fractions and number lines. You can also create projects for your students that they can independently work with. The app can also be used as a supplement for students who train with Number Quest Flex. With FLEX - Math Tools you as a teachers can facilitate understanding regarding the specific mathematical skills that are trained in the program. Please visit our website for more information. FLEX - Math Tools contains the following tools: • numbers • mathematical symbols • number lines • fractions - Rectangles • number bonds • number blocks • images

Screenshots

FLEX4 screens

Verdict

The call

The clearest difference is review sentiment: Duck Duck Moose Reading HD at 43% against FLEX's 0%. FLEX's advantage is device support (3 vs 1). On price, update cadence, ads and in-app purchases 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. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Duck Duck Moose Reading HD ships an update every 11 months, FLEX every 19 months. The most recent releases landed on October 22, 2026 and October 29, 2026 respectively.

Scorecard2 real differences · 8 level
Duck Duck Moose Reading HD versus FLEX: the parameters behind the verdict, then further details
ParameterDuck Duck Moose Reading HDFLEX
PriceFreeFree
Rating4.1 (32 ratings) — better—
Positive reviews43.5% of reviews — better0.0% of reviews
Number of ratings32 — better—
Update frequencyEvery 11 months — betterEvery 19 months
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPadiPhone, iPad, iPod — better
Requires iOS9.0 — better9.3
Further details — not scored
Size55 MB7 MB
Age rating4+4+
DeveloperDuck Duck Moose LLCLeripa AB

Customer experience

Duck Duck Moose Reading HD

All ratings30 ratings
Positive76.7%
Neutral10.0%
Negative13.3%
Written reviews23 reviews
Positive43.5%
Neutral17.4%
Negative39.1%

FLEX

Written reviews1 reviews
Positive0.0%
Neutral100.0%
Negative0.0%

In-app purchases

None

Duck Duck Moose Reading HD

No in-app purchases

None

FLEX

No in-app purchases

Questions

Is Duck Duck Moose Reading HD free?
Duck Duck Moose Reading HD is free to download, with no in-app purchases.
Is FLEX free?
FLEX is free to download, with no in-app purchases.
Do Duck Duck Moose Reading HD or FLEX have ads?
Neither Duck Duck Moose Reading HD nor FLEX shows ads.
Which is updated more often, Duck Duck Moose Reading HD or FLEX?
Duck Duck Moose Reading HD ships an update every 11 months, and FLEX every 19 months. Most recently, Duck Duck Moose Reading HD was updated on October 22, 2026 and FLEX on October 29, 2026.

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