The History of Keeping Count
Like Duolingo, but for The History of Keeping Count. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
For the part of you with thirty open tabs that never became anything.
A short one: 12 levels across 2 sections, about 24 minutes end to end, roughly 5 days at five minutes a day. It moves through The First Marks and Scaling Your Progress. It starts from scratch.
Free forever · No credit card · iPhone & Android

Key ideas in The History of Keeping Count
- Internal counting is easily interrupted by distractions
- The human eye can instantly recognize small groups (like 5) without counting
- A physical mark acts as a 'saved' state of the count
- The 'five-bar gate' (four vertical, one diagonal) turns a long string of data into manageable chunks
- External memory allows the counter to focus on the movement of the sheep rather than the total sum
- Subitizing is faster and less prone to error than linear counting
- How tally marks function as external memory to prevent counting errors
- The efficiency of subitizing through grouping
- Physical notches provide a permanent record of a debt or quantity
- Material evidence prevents one party from lying about the agreed-upon amount later
- The 'split tally' (breaking the stick in half) ensured both parties had an identical, tamper-proof receipt
- A notch represents a 1-to-1 relationship with a real object
- The notch is a symbol that exists even when the object is gone
- Abstraction allows us to handle 'quantities' without the physical items present
- The role of physical tallies in establishing trust and permanence
- The progression from physical objects to abstract symbols
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives The History of Keeping Count the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
What is the term for the brain's ability to instantly recognize a small quantity without counting each item individually?
Get it right to open this lesson and 11 more in the app.
Where The History of Keeping Count takes you
Discover how humans moved from simple notches on bone to complex systems of tracking progress. Learn the mathematical breakthroughs that allowed us to count anything from sheep to stars.
- 1
The First Marks
- The Power of the Tally
- Tokens and Correspondence
- 2
Scaling Your Progress
- The Magic of Place Value
- Visualizing the Goal
2 sections · 4 units · 12 levels. Built to play, not to enroll.
You pick the voice
The History of Keeping Count is taught in the The Professor style: clear, structured, thorough. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Start The History of Keeping Count today.
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