# Browsing category arithmetic

## “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 —

## 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