Each year, most of us throw out our old calendar and replace it with a new one. Each month, we flip our calendar forward another page, and if we ever need to know which day-of-the-week corresponds to a particular day/month combination, we have to either calculate it ourselves or flip forward/backwards to the relevant month. Simple but curious questions, such as:
Aren’t so easy to figure out unless you actually flip to the needed month (or look up all of the months) to figure out what the proper answer is.
But it turns out that, mathematically, the answer to these questions — or any question where you want to match up the day of the week with the day/month combination in a year — are extremely predictable, straightforward, and simple to figure out. If, that is, you don’t restrict yourself to using a conventional 12-month calendar, but rather use this one-page calendar that not only lasts the whole year, but that’s extremely easy to adjust for any/all years you’ll encounter into the future. Let’s show you what it’s all about.
Above, you can see the 2023 iteration of a one-page calendar. On the lower-left, you can see the days of the month, which works for all months as long as you know that: