As a special not-birthday treat, my wife took me to the optometrists. He (the optometrist, not my wife) said my prescription had changed "a little bit", but when I compared the two sets of numbers I could detect no correlation between them whatsoever.

[Rab] Were you wearing glasses at the time?

(rab) Date of birth 9 Oct 1975 at 5 a.m. then? I have taken a century as 36524.25 days. On 18 July this year at 6 pm I shall be two-thirds of a century old. On 23 July last year I was twice as old as you. I do like faffing about with a calculator.

Rosie old chap, too much time on your hands? Very good though!

(Bigsmith) I see mathematics (or arithmetic, which this is) as a recreation. Time to spare? Work out my date of birth. (Don't forget the leap years, all n of them.)