Hello 👋 I'm Heron
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.
Coming to iPhone first.
Second lesson
Squaring any number ending in 5
Drop the 5, you're left with n. Multiply n × (n+1), then stick 25 at the end. That's it.
Examples:
35² → 3 × 4 = 12 → 1225
125² → 12 × 13 = 156 → 15625
Why it works: (10n+5)² always ends in 25. The rest is just n climbing one step up.
Start testing
Board review: 18% margin from $87K revenue. How much is this in $K?
Now find
5%
Just divide the 10% you got by two: that will be 5% of the original number
5% of 87 (8.7 / 2) =
Hint
Next
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
THE CONTRAST
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 & 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.
~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.”
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.
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.
House of the Founder
Your drills are now tailored to real venture scenarios: runway, equity, and scaling costs
Choose the house
House of Daily Life
Everyday numbers without the phone.
Tips, sales, bill splits, and household math.
Choose the house
House of the Closer
Deal-floor math when the client is watching.
Discounts, commissions, real-time quotes, no calculator out.
Choose the house
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.
#3 place
Alex (You)
12 techniques learned
1,482 XP
to Gold league: 2,000 XP
Leagues and tournaments
Earn XP, compete with other players in weekly league tournaments, and climb from Plastic to Diamond league.
Techniques
Master mental math with these shortcuts
Search techniques...
Learned
Squaring Numbers Ending in 5
Multiply the tens digit by the next integer up, then append 25. E.g., 35² → 3×4=12, so the answer is 1225.
In process
Multiplying by 11
Add the two digits of any 2-digit number and insert the sum between them. E.g., 11×53 → 5_(5+3)_3 = 583.
unLearned
The 9s Trick
Multiply by 9 by multiplying by 10 and subtracting the original number. E.g., 9×8 = 80−8 = 72.
unLearned
Left-to-Right Addition
Add the largest place values first, then work down. E.g., 347+589 → 800+130+6 = 936. Reduces mental load.
40+ superpower techniques
Each of the 40+ techniques. Quick multiplication, mental percentages, and estimates all feel like magic.
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.
CheckedThe habit of checking
Someone else's discount, invoice or “average” gets a quiet check on the fly.
No IQ claims. Just daily reps your head actually uses.
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
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.
Join the WaitlistThirty minutes of feed.
Five minutes of drills.
Attention is a currency. Spend it where it pays you back.
Daily drill
$174 ÷ 6 = ?
Split the dinner bill in your head
Your path
Day 1
A short consultation tunes the app to your field. You learn your first technique the same day.
House of the Founder
Choose the house
Every day
One five-minute session: learn a trick in two minutes, drill it on your numbers, use it the next time that number comes up. The streak forgives a bad day.
5:00
Week by week
Techniques stack. Drills 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
First in line
Access rolls out in signup order. Join today and you're in before the crowd.
Founder's price
Early joiners lock $4.99/mo instead of the $9.99 launch price. For good.
A say in what ships
Early feedback decides which techniques and Houses come first.
QUESTIONS & ANSWERS
Got questions?
We've got answers.
Not at all. The techniques start from zero and build up. If you can multiply single digits, you're ready.
Stop reaching for the calculator.
Join the waitlist and start mastering 40+ math techniques that feel like magic.
Coming to iPhone first.
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