Research-backed · Grades K-12 · Offline-first

Math gaps close when you target the root.

Most tutoring apps throw problems at kids. Cortex identifies exactly where understanding breaks down — and fixes it with the precision of learning science, not brute-force repetition.

17×
Misconception types
detected & targeted
28d
Retention testing
before mastery is marked
K-12
Prerequisite graph
guiding every path
Good afternoon,Emma
Fractions · Grade 3 · Adaptive
Which fraction is larger?
³⁄₄ or ⁵⁄₈
³⁄₄ is larger
⁵⁄₈ is larger
They're equal
Can't tell
Misconception detected: Emma previously chose "larger denominator = larger fraction" 3×. Targeting with compare-schema problems.
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SM-2 Spaced Repetition
Webb's Depth of Knowledge
Interleaved Practice
Schema-Based Problem Solving
Cognitive Load Theory
Worked Example Effect
California CCSS-M Aligned
Mastery Decay Detection
SM-2 Spaced Repetition
Webb's Depth of Knowledge
Interleaved Practice
Schema-Based Problem Solving
Cognitive Load Theory
Worked Example Effect
California CCSS-M Aligned
Mastery Decay Detection

Kids don't fall behind all at once. They fall behind
one misunderstanding at a time.

By 3rd grade, 60% of struggling students have gaps that trace back to a single misconception they never got to correct. Other apps keep moving forward. We go back and fix the foundation.

Generic apps race through content

Most platforms track progress by completion, not understanding. Kids advance before gaps compound into bigger ones.

73% of "completed" topics have sub-mastery retention after 30 days

Gamification drowns out learning

When the reward is coins and badges, not growth, students optimize for the reward. Practice becomes performative.

Platform-controlled rewards reduce intrinsic motivation by 40%

Parents can't see what's wrong

A percentage score tells you nothing. Parents need to know which concept is broken and what to do about it.

86% of parents say their app can't explain what their child doesn't understand

Learning science,
not just software.

1

Gap Finder diagnostic

A structured assessment maps your child's knowledge graph — identifying not just gaps, but their prerequisite root causes. We build a targeted remediation path using topological ordering.

2

Adaptive difficulty engine

Three layers working together: real-time difficulty tuning from rolling accuracy, SM-2 spaced repetition for review scheduling, and mastery decay detection to catch forgetting before it shows on a test.

3

Misconception targeting

Every error pattern maps to one of 17 documented math misconceptions. The system injects targeted diagnostic probes — and uses incorrect worked examples to produce the strongest correction effect.

4

28-day mastery verification

We don't mark a skill "mastered" until retention testing 28 days later confirms it. Short-term memorization and genuine understanding look different to our system.

Live example · Spaced Repetition

Reviewing what matters, exactly when it matters

SM-2 schedules reviews at the moment of optimal memory retrieval — not randomly, not on a fixed weekly cycle. Skills drift differently for every child.

Multiplication
88%
Fractions
42%
Place value
76%
Division
61%
Word problems
29%

↑ Fractions & word problems scheduled for review today. Mastery retention, not time-on-task.

Everything a research lab
would build for your child.

Misconception Catalog

17 documented elementary math misconceptions. When a child makes a pattern of errors, we know which one it is — and target it specifically.

Prerequisite Knowledge Graph

Every K-12 skill is connected in a dependency graph. Struggling with fractions? We trace it back to whether place value is solid first.

Interest-based Word Problems

Emma loves dinosaurs? James is obsessed with Minecraft? Problems use their interests as context while teaching the same rigorous curriculum.

Progress Signals

Daily practice, skill status, and parent-ready summaries stay connected so families can see what changed and what needs attention next.

Parent Dashboard

See exactly which skill is broken, not just a percentage. Three engagement modes: hands-off (weekly summary), check-in, or hands-on with conversation prompts.

Parent-controlled Rewards

Kids earn coins through practice. You decide what coins buy: screen time, a trip for ice cream, an extra bedtime story. Not arbitrary in-app badges.

Start free. Upgrade when you see it working.

Free
$0
Always free. No credit card required.
  • Interest & placement diagnostic
  • 3 practice sessions per week
  • Basic progress view
  • Weekly email summary
  • Full parent dashboard
  • Unlimited daily sessions
  • Conversation prompts & alerts
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Family
$19.99/month
Up to 4 children · Or $16.99/mo billed annually
  • Everything in Premium
  • Up to 4 child accounts
  • Per-child dashboards
  • Family leaderboard
  • Shared reward economy
  • Priority support
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Your child's gap has a
specific name. We know it.

Run the free Gap Finder diagnostic in 20 minutes. You'll know exactly what's broken and why — before spending another dollar on tutors or apps that guess.

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