January 10, 2025
New Year traditions… and here’s my math-brainteaser one!
Happy New Year*, folks!
From the back end of each year and into the beginning of the following one, quite a few traditions are observed around the world. There’s “Catholic” Christmas on December 25 (that’s how it’s referred to in Russia!); there’s New Year (universally celebrated); and there’s Orthodox Christmas on January 7. In connection with the latter, there’s also another tradition of my own – my explaining why I tend to be quiet on these here blog-pages from late December to just after Orthodox Christmas, and why my “Happy New Year” greeting can seem, to some, several days late*: each day is a public holiday in Russia (this year: December 29 – January 8). But wait… There’s yet another tradition – also of mine: my festive mathematical brainteaser!…
The… necromancy of numbers, the elegance of equations… Yes – I am a mathematician by training, and yes – I never let you forget that early January of each year. But of course I don’t: for what better way is there to blow away the cobwebs of gloom brought on by the January blues?…
All righty. Explanations done. Let’s get to this year’s number-crunching riddle (actually – riddles)…
Top-level brainteaser
Using basic math (adding, subtracting, multiplying and dividing; brackets), turn “10 9 8 7 6 5 4 3 2 1” into the number of this year – 2025, neither changing the order of the numbers, nor combining them (e.g., 43+1+2).
For example, ((10 + 9) * (8 + 7) * (6 + 5) * 4) / 3 / 2 + 1 = 2091, but that’s no good as we need to get 2025.
