Do math in your head. From grocery prices to company valuations
Do math in your head.
From grocery prices to company valuationsOver 40 proven mental math techniques that are easy to learn but feel like magic. The app adapts to your field: founders, sales, marketers.
Join the Waitlist
Meet Heron, your
mental math coachHe'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
Adapts to your pace
Celebrates your wins
No rigid mathematical jargon. Heron breaks down shortcuts using simple, intuitive concepts|
Calculates your cognitive speed in real-time. Automatically dials back the difficulty or pushes you harder to maintain flow state.|
Whether it's matching your 10-day streak, gaining 200 XP, or climbing up to the Diamond League, Heron is there to hype you up.|
The contrast
Stop satisfying your curiosity
with slow Google searchesA 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 & UNCERTAIN
THE 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.
- 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.
\~30 sec
of fumbling while everyone at the table watches you Google basic finance.
With Founder's Math
INSTANT & POWERFUL
RULE OF 72
“8 years. Answered instantly.”
< 2 sec
to deliver a confident answer, impress the room, and show you truly understand compound growth.
A sharper head, not
just faster mathNo IQ claims. Just daily reps your head actually uses.
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 machineForget 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
Experience the magic
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
Show me how
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.
30:00
Daily session
12
5:00
Split the dinner bill in your head
$174 ÷ 6 = ?
Hint
Check
1234567890
9:41
Blog
Latest articles
The 7 times table: five plus twoSeven is five and two, so 7 × 8 is 40 plus 16. The table to 12, the split, and ten questions to practice.Read →
The 8 times table: double, double, doubleEight is two doubled twice, so 8 × 7 is 7 doubled three times. The table to 12, the trick, and ten questions to practice.Read →
13 Christmas riddles you can solve at the tableA stable with 14 heads and 40 legs, a tree an inch too tall for the ceiling, and a package that lands four seats short.Read →
Your path
Day 1
A short consultation tunes the app to your field. You learn your first technique the same day.
Every 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.
Week by week
Techniques stack. Reps adapt to where you slip. The app raises the bar as you grow.
The goal
The check lands on the table, and you've already split it: before anyone reaches for a phone.
Day 1
A short consultation tunes the app to your field. You learn your first technique the same day.
Every 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.
Week by week
Techniques stack. Reps adapt to where you slip. The app raises the bar as you grow.
The goal
The check lands on the table, and you've already split it: before anyone reaches for a phone.
Why join now
Founding member
A numbered badge in your profile and in the leagues, for the first 1,000. It stays for good.
Founder's price, for good
$4.99 a month instead of $9 at launch, locked for as long as you stay.
Vote on what ships
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.
Questions & Answers
Got questions?
We've got answers.How do I get better at mental math?
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.
Do I need to be good at math to start?
No. The techniques start from zero and build up. If you can multiply single digits, you're ready, and the first day sets your level and pace.
What techniques does the app teach?
Over 40 of them: tips and bill splits, percentages and discounts, the Rule of 72, squaring numbers that end in 5, quick multiplication and mental division.
Is this just for founders?
No. Founders, sales, marketers or everyday life: the app tunes its tasks to your field, so you train on the numbers you actually meet.
What is the best app to practice mental math?
Look for one that teaches a technique and then makes you practice it, because apps that solve problems for you leave the calculating to the phone. Founder's Math gives you reps on numbers from your field.
When does the app launch?
The iPhone app is in final polish. The waitlist gets access first, in signup order, so joining today puts you ahead of the line.
Will there be a free plan?
There is a 7-day free trial, so you try real techniques before paying. After that it is $9/month or $90/year at launch, and early waitlist members lock a founder's price of $4.99/month or $59.88/year.
Stop reaching for
the calculator.Join the waitlist and start mastering 40+ math techniques that feel like magic.
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