Blog Marco

Here were some exerpts from the past week regarding mathematical magic tricks. For those who love maths, you won't be fooled but for other people, here it is:

"We haven't dabbled in mathematics for a while, and it's time that we did. At least, that's what Mick Costelloe, of South Coogee, reckons. He wants to know how this works: "Grab a calculator," he writes. "You won't be able to do this in your head. Key in the first three digits of your phone number (but not the area code or the first 9). Multiply by 80. Add 1. Multiply by 250. Add the last four digits of your phone number. Add the last four digits of your phone number again. Subtract 250, and divide the result by 2. Recognise the answer?" Mick reckons that this is "Pretty cool!" and indeed it is. Why is it so?"
smh col-8 10/11/05

If you do the above make sure you press equals after each command. And of course this is 'configured' for Sydney numbers, or I guess any other phone number with seven digits.

"Don't you love those questions for people who are not good at algebra?" asks Bruce Miles, of Abbotsford. That's the kind of rhetorical query that sends a shiver up Column 8's spine, as in: "Uh oh, look's like we've exposed ourselves as ne're-do-thinks with yesterday's 'pretty cool' maths item." Bruce was one of dozens of readers with basic high-school maths skills to expose the phone-number trick as a roundabout way of getting back to the number you first thought of.