# johnpholder

## John

## About StumbleDNA StumbleDNA

## The Triangle Problem or What's Wrong with the Obvious Truth...

I'm interested in and write about a wide variety of topics - economics, psychology, marketing, music, etc. I prefer writing long articles to short posts and don't update very often.

## Brothers in Binary - Futility Closet

## Touch Mathematics | Trigonometry

A collection of free, web browser-based apps that aim to make mathematics intuitive for learners of all ages.

## age calculator at Math Cats

age calculator: how old are you in years, months, weeks, days, minutes, or seconds???

## math-fail.com

## A Date Idea Analyzed

I don't do conventions very often, but I recently went to out in Northampton, MA, while visiting some friends. While I was there, I had a guy propose something fascinating to me. I can't remember the guy's name, so if he or one of his friends sees...

## elementary number theory - Deleting any digit yields a prime......

## upload.wikimedia.org

## The Answer Wheel | Futility Closet

## 10 readers' favourite numbers

On Friday, the Magazine marked the death of Jerry Nelson, the puppeteer behind Sesame Street's Count von Count, by revisiting a BBC radio interview in which the Count said his favourite number was 34,969 (187 squared).

## Geeky pin numbers - Spiked Math

Geeky pin numbers - Spiked Math Comic - A daily math webcomic meant to entertain and humor the geek in you...