The mobile phone has a calendar making planning easier than ever. But for those who love to play with numbers, the calendar can be a fun game. You can keep the entire year’s calendar in your mind if you can remember 12 numbers, one for each month. Be prepared to do a little arithmetic too. It’s fun if you love numbers.
Can you memorise those numbers? Easy, right? Now what do you do with them?
The first number is for January, the second for Feb, and so son.
Let’s see which day of the week is the next Republic Day. The Republic Day is on Jan 26. Add the number for Jan to the date.
26 + 4 = 30
Now divide that sum (30) by 7. The quotient (the answer you get when you do the division) is immaterial for us. We only need the reminder. In this example, the reminder is 2.
30 ÷ 7 = 4 & reminder 2
So Jan 26 is Tuesday.
If the reminder is 0, it’s Sunday.
Reminder 1 = Mon
Reminder 2 = Tue
Reminder 3 = Wed
Reminder 4 = Thu
Reminder 5 = Fri
Reminder 6 = Sat
Which day is Independence Day?
The number for August is 6. Add that to the date.
15 + 6 = 21
21 ÷ 7 = 3, no reminder. Hence, Sunday.
Work out as many examples as you like.
Now how does a month get its number. Simple. Just subtract the date of the first Sunday from 7.
Example: The first Sun of Jan 2021 is 3rd.
7 – 3 = 4, which is the number for Jan.
You can make mental calendar for any year using this.
Let me add a personal touch to this. I have been using the mental calendar right from my boyhood. I first learnt about it from a children’s magazine when I was in high school. Ever since I have relied on the mental calendar. It takes just a few seconds to find out the day of any date once you are used to this.