Wonder why random values of 2.303 are "hidden" in formulae? To make them easier to use with a slide rule.
A slide rule? The last slide rule slid out the door of Keuffel & Esser in 1975 (they sent their engraving equipment to the Smithsonian). You can still find them, used and even new - still packaged up to sell to engineers and scientists. The Oughtred Society has a online museum, as well.
We still have my mother-in-law's K&E, in it's leather case with her name impressed into it. Family history says she bought it with the money she earned tutoring Jackie Robinson in chemistry at UCLA.
It's the nine thousand one hundred and thirty first day since Math Man and I walked through the doors of the parish church, processed down the aisle and vowed to stand by each other and cherish each other in weal and in woe.
It's our 25th anniversary, if you don't want to do the math (yes, Math Man included the leap years!). It's not a prime number, but composite, with a prime factorization of 23 x 397.
Our sons had a life sized photo cutout of us made and restaged the wedding — right where it happened in our parish church. It is an entirely different take on renewing your vows. They photographed the 'event' and gave us the photos (and the cutout) for an anniversary present.