Essay · Calculator
A 20% drop needs more than a 20% recovery.
Follow a $100 price down to $80 and back. Use the calculator to see how the required rise changes with the size of the drop.
The collection
Writing
Essays, worked examples, and tools. Each title takes you to the original piece.
Everyday numbers
Start with two workweeks with the same average to see what a summary hides. Then read the support-desk example to see what happens when the mix itself changes.
Blogger · Guide
Before You Compare Two Numbers
A team finishes more tasks but meets less of its plan. Use the worked comparison to separate counts, percentages, and percentage points.
Wix · Guide
What an eight-hour average leaves out
Two workweeks share a mean and a median. Only one breaks a ten-hour daily limit. Try the same check on your own comparison.
Scribd · Two-page guide
Both Groups Improved. The Overall Rate Fell.
A support desk gets better at both kinds of request while its overall success rate falls. Hold the workload mix steady to see what changed.
Netlify · Essay and calculator
The growth that empties your bank account
A distributor adds $1 million in sales and needs about $181,000 more cash. Change the payment terms, inventory days, and collection time to see what moves the funding gap.
Carrd · Worksheet
Offer Comparison Desk
Copy a side-by-side worksheet and try the worked examples to see how fees, pack sizes, and subscription terms change what you pay.
Telegraph · Experiment
Why Two Dice Don’t Give Every Total the Same Chance
Count the 36 possible rolls, predict which totals will come up more often, and test your prediction with two dice.
Everyday science
Compare what a fan does to the air with what an appliance does to your power bill. In one case, follow the heat. In the other, track how long the device runs.
Framer · Illustrated essay
Why Your Phone Makes Mountains Look Tiny
Three diagrams and a simple experiment show what changes when you step back and zoom, and what changes when you only crop.
Essay
A fan cools you. Does it cool the room?
Follow the heat from your skin into the room and see what an open window changes.
Jimdo · Worked example
Why a Small Device Can Use More Electricity Than a Powerful One
A kettle and a router show why time matters as much as wattage. Estimate a device’s running cost from its power, running time, and your electricity rate.
Blogger · Illustrated lesson
Read motion graphs without guessing
Follow a cart through a pause and a reversal. Read speed and velocity from a graph, then see how the same four measurements can hide a different route.
Wix · Worksheet
Double the Dimensions and Count the Area Again
Double a rectangle, work backward from a target area, and use a short worksheet to check what changes in two and three dimensions.
Practical AI
Before a recommendation, find the missing detail. Once you have an answer, stress-test the plan or check the summary against the source.
Essay · Reusable prompt
When an AI should ask instead of answer.
Give a missing detail two plausible values. If they lead to different recommendations, you’ve found the question worth asking.
Mataroa · Worked example
The One-Minute Check Before You Trust an AI Summary
A pottery-class email shows how a tidy summary can lose a fee, an eligibility rule, or an unconfirmed date. Check the detail your next step depends on.
Neocities · Worked example
Before You Follow an AI Plan, Try to Break It
Stress-test a parcel pickup before a noon appointment. Separate deadlines from estimates, add a delay, and decide what you’d drop if time ran short.
Google Sites · Worksheet
How to Check an AI Summary Before You Send It
After the one-minute email check, try a fuller exercise. Compare a flawed summary with fictional meeting notes and check decisions, costs, owners, and deadlines.
beehiiv · Build guide
Your First AI App Doesn’t Need to Be Impressive
Build a small unit-price calculator with AI, then test it with comparisons where you already know the answers.
Everyday decisions
Use the support guide to ask for a specific next step. Once someone gives you a follow-up date, the reminder guide shows how to turn that date into a cue you can act on.
SITE123 · Guide
Practice the Reply You’re Afraid to Hear
Rehearse the pushback in a difficult conversation, then practice offering a tradeoff the other person can decide on.
Blogger · Guide
A Reminder Needs a Trigger, Not Just a Date
Choose a time, event, or place when you can actually act. A five-part prompt helps you write a reminder that tells you what to do.
Wix · Guide
How to Get Past the Customer Support Loop
Use a four-line case summary and ready-to-adapt follow-ups when support keeps asking you to start over.