If I place a block on a conveyer belt moving at 10m/s then place that conveyer belt on another conveyer belt moving at 10m/s in the same direction the block would now be moving at 20m/s. We are always told it is impossible to get things quicker than the speed of light but with enough conveyer belts moving at high enough speeds why would it not be possible to get the block moving this fast? All impracticallities aside

I would often lull myself to sleep by picking a number then trying to work out if it is prime. Eliminating the possible factors by number crunching usually gets as far as 19 or 21 before sleep takes over. I've never managed to finish for any non trivial number above 200.

I decided to find out how many results Google returned when performing a search for numbers 0-10. All of them returned results between 7-17 billion, apart from 9, which returned less than 1 billion.  Can anyone think why?