Don't miss** BBC Radio 4's In Our Time program on Negative Numbers. You listen at the website to this proramme until Thursday morning, when they replace it with the next one. Here's the blurb for the ...

Numbers don’t stop at zero. They continue into negative numbers as you count backwards. If you start at 2 and count backwards, you get 2, 1, 0, -1, -2, and the numbers keep going. Take a look at the ...