First off, it may have been more years since I was in school than many of you have been alive. Anyway, a long time. But, I have always had number patterns running through my head, although not to the extent of a John Nash.
So, recently, I started working on multiplication in my head. I started with 8x8, then 7x9, 6x10, and so on. I noticed that the difference in the product scaled down in an odd pattern of 1, 3, 5, etc. I'm sure there must be a name for this. It appears to work for numbers of any size, and I made a small spreadsheet to prove it to myself. So, nothing earth-shattering. Just a curiosity.
So, recently, I started working on multiplication in my head. I started with 8x8, then 7x9, 6x10, and so on. I noticed that the difference in the product scaled down in an odd pattern of 1, 3, 5, etc. I'm sure there must be a name for this. It appears to work for numbers of any size, and I made a small spreadsheet to prove it to myself. So, nothing earth-shattering. Just a curiosity.