Browsing category arithmetic

Decimal curiosities

There's not much of a story to this post, except for a few curiosities the decimal system throws up (largely as a result of the binomial expansion). Some time ago, I looked at some Fibonacci witchcraft: $\frac{1}{999,998,999,999} = 0.000\,000\, 000\,001\, 000\,001\, 000\,002\, 000\,003\, 000\,005\, 000\,008\,...$, neatly enumerating the Fibonacci sequence

Read More

“Destiny”

The following puzzle/trick came up on Futility Closet, one of my favourite sites for recreations. Here's how they describe it: Arrange cards with values ace through 9 in a row, in counting order, with the ace on the left. Take up a card from one end of the row —

Read More

Ask Uncle Colin: Multiplying negatives

Dear Uncle Colin, I'm finding it hard to understand why, when you multiply two negative numbers together, you get a positive number. I accept that it's true, but I was brought up to believe that two wrongs don't make a right. -- Positive Equals A Negative Otherwise? There is a

Read More

Sign up for the Sum Comfort newsletter and get a free e-book of mathematical quotations.

No spam ever, obviously.

Where do you teach?

I teach in my home in Abbotsbury Road, Weymouth.

It's a 15-minute walk from Weymouth station, and it's on bus routes 3, 8 and X53. On-road parking is available nearby.

On twitter