Random numbers
October 19th, 2005 | by mbhunter |I’m one of those people who has a mind for numbers. (After all, I was teethed on a calculator.) I can’t remember where I put my keys, but I can rattle off the first eleven digits of pi — 3.1415926535 — (yeah … yeah … I’m an excellent driver …)
One of those random where-have-I-seen-that-number-before moments just happened.
My wife got me a Willow Tree New Dad figurine because 1) it looked like me a bit and 2) I thought it was really cool-looking. As I was cleaning off my desk, I saw the model number of the figurine — #26129.
That’s the same as my account number for the LemmingRun.com traffic exchange.
What does this have to do with personal finance? Well, probably nothing directly, but personal finance is full of number tricks:
- Rule of 72 — The product of the number of years to double your money and the interest rate in percent is about 72. (If you invest at 8%, your money will double in about 9 years — 8 times 9 is 72.)
- Calculating a tip — If you have an 8% sales tax, double the tax to give 16% as a tip.
- Biweekly mortgage payment acceleration quickie — Paying half of your mortgage every two weeks is just about the same as making one extra payment a year. So take your payment, divide by 12, and contribute this additional amount toward principal each month.
Do you have any number tricks you use for quick calculations?
