Do math in your head.
From grocery prices
to company valuations
Over 40 proven mental math techniques that are easy to learn but feel like magic. The app adapts to your field: founders, sales, marketers.
Meet Heron, your
mental math coach
He's witty, sharp, and slightly obsessed with numbers. Think of him as your smart friend who always solves dinner bill tips in a flash.
Explains like a friend
No rigid mathematical jargon. Heron breaks down shortcuts using simple, intuitive concepts
Stop satisfying your curiosity
with slow Google searches
A mental calculator isn’t just about speed: it’s about having instant answers that make you look sharp, prepared, and in command of any financial conversation.
Without Founder's Math
SLOW & UNCERTAINTHE CHALLENGE
“How many years until my investments double at 9%?”
Open Google and type “how long to double investment at 9%.”- Scroll past ads, open a compound interest calculator.
- Enter the numbers, second-guess the result, try another site.
~30 sec
of fumbling while everyone at the table watches you Google basic finance.
With Founder's Math
INSTANT & POWERFULRULE OF 72
“8 years. Answered instantly.”
- Apply the Rule of 72: divide 72 by the annual rate.
- 72 ÷ 9 = 8 years to double your investment.
- Works for any rate. 6%? → 12 years. 12%? → 6 years.
< 2 sec
to deliver a confident answer, impress the room, and show you truly understand compound growth.
A sharper head, not
just faster math
Memory
Numbers stop slipping away: you hold the three figures of a conversation without writing them down.
Focus
A trick is a chain of steps. Training the chain trains the attention that holds it.
The habit of checking
Someone else's discount, invoice or “average” gets a quiet check on the fly.
Learn playfully,
calculate like
a machine
Forget boring textbooks. Our gamified learning system makes mastering techniques simple and addictive: every trick feels like a discovery.
Tasks from your field
The app adapts to your profile: founders get tasks on burn rate, runway, and cap tables; sales reps on conversion, margins, and deal size.
Gamified learning
A well-designed progression system: master techniques step by step, from simple to complex. Every new trick is a small victory.
Leagues and
tournaments
Earn XP, compete with other players in weekly league tournaments, and climb from Plastic to Diamond league.
40+ superpower
techniques
Each of the 40+ techniques. Quick
multiplication, mental
percentages, and estimates all feel like magic.
Mental math is taken seriously at the
world's best schools
TRACHTENBERG ZURICH
TRACHTENBERG ZURICH
See the magic
yourself ✨
Think mental math is only for geniuses? Give this 2-second technique a try and witness your brain speed up immediately.
45² =
Try squaring 45 in your head
Use the multiplication formula for numbers ending in 5
The "Ending in 5" Formula:
1
Drop the 5: You are left with 4.
2
Multiply by the next number: 4 × (4 + 1) = 20.
3
Just append 25: Put 20 and 25 together to get 2025!
This simple trick works for any number ending in 5 (e.g., 85² → 8 × 9 = 72 → 7225). This is just 1 of 40+ techniques.
Thirty minutes of feed.A five-minute session.
Daily session
Split the dinner bill in your head
$174 ÷ 6 = ?
Latest articles
25 riddles with answers where the answer is the cheap partThree ducks answer all three lines at once, and most of us add the lines up to five. Twenty-five riddles with answers, plus the move behind each.Read →
30 hard riddles for adults where knowing more hurtsA hole hands you three measurements and every one of them is honest. Thirty riddles with answers, and the reason the wrong one felt right.Read →
Multiplication strategies: five moves and when to use eachFive moves cover the whole chart, and a second move checks the first. 8 × 9 comes out 72 three different ways, plus nine questions to practice.Read →Your path
A short consultation tunes the app to your field. You learn your first technique the same day.
One five-minute session: learn a trick in two minutes, practice it on your numbers, use it next time. The streak forgives bad days.
Techniques stack. Reps adapt to where you slip. The app raises the bar as you grow.
The check lands on the table, and you've already split it: before anyone reaches for a phone.
A short consultation tunes the app to your field. You learn your first technique the same day.
One five-minute session: learn a trick in two minutes, practice it on your numbers, use it next time. The streak forgives bad days.
Techniques stack. Reps adapt to where you slip. The app raises the bar as you grow.
The check lands on the table, and you've already split it: before anyone reaches for a phone.
Why join now
A numbered badge in your profile and in the leagues, for the first 1,000. It stays for good.
$4.99 a month instead of $9 at launch, locked for as long as you stay.
See all plans
Founding members vote on the next techniques and Houses. What wins ships with their name on it.
Until launch: a five-minute session in your inbox every week.
Got questions?
We've got answers.
Learn one technique at a time, then practice it until it is automatic. Founder's Math runs that loop in one five-minute session a day: two minutes to learn, the rest for reps.
Stop reaching for
the calculator.
Join the waitlist and start mastering 40+
math techniques that feel like magic.
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