Doomsday rule

The Doomsday Rule is a quick way to figure out what day of the week a certain date is on. It works by memorizing just 7 numbers (called the Doomsday numbers), and then doing a few basic steps to figure out the day of the week. Here's how it works:

First, you need to memorize the Doomsday numbers:

January: 4
February: 4
March: 0
April: 6
May: 2
June: 4
July: 0
August: 6
September: 3
October: 5
November: 1
December: 3

Now, you can use the Doomsday Rule to figure out the day of the week for any date.

1. To start, figure out what the last two digits of the year you're looking at are.
2. Then, look at the Doomsday number for the month of the date you're looking at.
3. Add the Doomsday number for the month and the last two digits of the year together. That number tells you which day of the week the date you're looking at will be on.

For example, let's say you want to figure out what day October 28th, 2020 is. You would start by figuring out that the last two digits of the year are 20. Then, you would find the Doomsday number for the month of October, which is 5. You would add 5 and 20 together which gives you 25. 25 means the date you're looking at is on a Saturday.