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Notes on numbers

Short, plain-language pieces on the money and math questions people actually ask us — no jargon, no filler.

My GPA Didn't Move the Way I Expected, Until I Learned What Credit Hours Do

An A in a 1-credit lab barely moved my GPA, while a B in a 4-credit course dragged it down hard. Here's the weighting most students never get explained.

The "8 Glasses a Day" Rule Never Made Sense for My Body

Same 8 glasses for a 110-pound office worker and a 220-pound construction worker in July? Here's why hydration needs actually scale with weight, activity, and heat.

Why Your First Mortgage Payment Barely Touches the Loan

I expected my loan balance to drop steadily from month one. Instead almost my entire first payment went to interest — here's the amortization math nobody explains upfront.

I Stopped Chasing 8 Hours and Started Counting Sleep Cycles Instead

I used to treat 8 hours as a hard target and still woke up groggy. Turns out where your alarm lands inside a sleep cycle matters more than the total hour count.

I Ran the Same Route for a Year Before I Understood Pace

I spent a year tracking only distance and total time, and had no idea what to do with either number. Here's what changed once I started thinking in pace instead.

Percentages Broke My Brain Until I Stopped Doing Them One Way

There isn't one percentage formula, there are three different questions hiding under the same name — and mixing them up is where almost all the confusion comes from.

What Compound Interest Actually Does to Your Money

Everyone quotes Einstein about compound interest and moves on without explaining anything. Here's the actual mechanics, with real numbers, and why the first ten years feel like nothing is happening.

Your Tax Bracket Doesn't Work the Way You Think

I used to turn down extra freelance work because I thought it would push me into a "worse" bracket and shrink my paycheck. I was wrong, and so is almost everyone who says this at Thanksgiving dinner.

BMI Is a Blunt Tool — Here's What I Check Instead

My BMI has said "overweight" for three years of my life, including the year I could do more pull-ups than anyone at my gym. A closer look at what the number can and can't tell you.

The Rule of 72 Is the Only Money Math I Still Remember

I forgot almost everything from my one finance class in college except this one trick, and I still use it to sanity-check every investment pitch someone sends me.