Primes

83, 23, 17

83x10^6 years: age of fossilised leaf in my patio

6.03x10^23 Avagadro’s Number

1.00x10^17 approx age of universe in seconds 

If you do a search for your username, you will see one particular thread (the on about Top 5 Sports People) where your name (or the Hoy part) got mentioned a lot

Second for that rec Proddo, a great book.  One of those great pop science* reads that you walk away from thinking you totally get it (in this case iirc the riemann hypothesis).  Then you think about what you think you have "got" and realise you have t got a scooby.

*for these purposes maths is a science and anyone who disagrees is a willyface