So you think you know 2+2? Try again.
ON PAPER, IT’S ONE OF THE SIMPLEST maths problems in the world: 2+2. If you’re counting something, such as screws at the hardware store, it’s pretty straightforward. But the lines blur in other contexts. If you add two cups of vinegar to two cups of baking soda, and the reaction produces five cups of a fizzy mess, does that mean 2+2=5?
We bring assumptions into the world of mathematics. In this case, the simple ‘counting numbers’ – the whole integers 1, 2, 3, and so on – signify a
