Calendar In Mind: find day from date mentally

Tuesday, 2 April 2013

Chapter 1. Try It Yourself And Get Some Confidence

Before going in further details I would like to take you through a simple example and try my trick by yourself. So, are you ready…?? :)

All right then. Just make sure that you have a pen/pencil and a blank paper with you. Did you grab one…??

Okay then, let’s go for it –
Step 1. Choose any date from any month of the year 1990. I will choose 12th of April 1990, you choose any other.

Step 2. Now you have to do some math (Mathematics). Mathematics..??? Yes, you heard it right…!! But don’t worry it’s a simple math that you have learnt when you were a kid.

All you have to do is a simple addition.
Add the following numbers:
12 (This is the date I have chosen, put your date on paper.)
+
0 (From table given below the key number for the month April is 0, select key number for your month and add it to your date.)

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

+
1 (This is for 19 out of 1990, which means for the first two digits in year 1990. This will be the same for you also as you have chosen the date from year 1990. Haven’t you? But how did this 1 come? Well, you will realize it later as you will learn the trick in detail. So, don’t worry about it as of now.)

6 (This is for 90 out of 1990, which means for the last two digits in year 1990. And obviously this also will be the same for you. Again from where did this 6 come? The same answer for this also - don’t think about it right now. You will know everything later on as you read further...)

So, what is the addition?? For my case it is: 12+0+1+6=19. Calculate for yours. Calculated? Verify it again… Done?? Okay then, let’s move to the next and the last step.

Step 3. Now we have to find the remainder when our addition (obtained from Step 2) is divided by 7 (Note: always we have to divide the addition by 7 only).

If you already know how to find remainder then that is great. But if you don’t then don’t worry, I will tell you. See below how I find remainder for my case-
For my case the addition is 19. So, I will divide 19 by 7. I will find the multiples of 7 till the number 19 or a number greater than 19 comes.

7 x 1=7
7 x 2=7+7=14
7 x 3=7+7+7=21

In the step above I have got 21 and that is a number greater than 19. That is why I will stop here. But to calculate the remainder I will have to go one step back as 21 is greater than 19. So, I will choose 14 and subtract it from 19 and I will get: 19-14=5. And this, 5 is nothing but our remainder.(continued in the next post)

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Calendar In Mind

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Friday, 27 September 2013

How to find the day from any date mentally?

Tuesday, 2 April 2013

Chapter 1. Try It Yourself And Get Some Confidence