# Abstract

IMPROVE YOUR MEMORY UPTO FIVE HUNDRED PERCENT WITHIN FEW HOURS

**HOW TO MENTALLY CALCULATE THE DAY OF THE WEEK FOR ANY DATE**

# The Basic Steps

The basic steps for a date in the

years 2000-2099 are as follows:

Example date July 13th, 2004

- Take the last 2 digits of the year and add a

quarter onto itself. (04 + 1 = 5) - Get the corresponding code for the month.

(January = 6, February = 2, March = 2, etc. See month codes for details).

July = 5 - Take the day. (=13)
- Add the numbers together (5 + 5 + 13 = 23)
- Take away 7 (or multiples of 7) until a number

from 1-7 is left. (23 – 21 =2) - This number corresponds to the day of the week.

(1 = Monday, 2 = Tuesday, etc.) In this case 2 = Tuesday

Other points

to take into account

Apart from the basic steps, other

elements have to be taken into account:

- When adding a quarter of the year onto itself, if

the quarter of the year is not a whole number, simply ignore the decimals.

Do not round up. Therefore 27/4 = 6.75 = 6, and 2/4 = 0.5 = 0.

- Leap years: subtract 1 from the total if the

month is January or February.

- Negative numbers. During the calculation you get

0 or negative numbers, just add seven until you get a number from 1-7.

- Different “centuries” *.
- 1700s add 5
- 1800s add 3
- 1900s add 1
- 2100s subtract 2
- 2200s subtract 4

(* For this method

we have to consider a ’00’ year as part of the new century)

The codes for

the months

At first the hardest part is learning

the codes for the months. They are as follows:

Jan |
Feb |
Mar |
Apr. |
May |
Jun |
Jul |
Ago |
Sept |
Oct |
Nov |
Dec |

6 |
2 |
2 |
5 |
0 |
3 |
5 |
1 |
4 |
6 |
2 |
4 |

Try to use some memory system to

remember the codes for the months. For example, February is the 2nd month,

March 2 music, etc. Try to find associations that will remind you.

If need be, you can add 7 or

multiples of 7 to any of these values to help you remember them. For example,

August could be 1 or 8, and as it is the 8th month, it may be easier to

remember with 8 than with 1. This may be useful if you can match it with a

well-known date. You could remember that the code for December is 25 (4+21), or

for someone’s birthday. The negative aspect of this is that you’ll be taking

away the 7 (or multiples) towards the end of the calculations, and you’ll be

working with bigger numbers.

Leap Years

- Remember that leap years are not always every 4 years. There are exceptions.

Years that end in 00 are not leap years unless it is a multiple of 400.

Therefore 1700, 1800, 1900, and 2100 are not leap years, but 2000 is.

The Gregorian

Calendar

- The calendar as we know it only came into effect (in England)

in 1752, replacing

the Julian calendar. Changes included cutting 11 or more days out of the

calendar and changing the first day of the year from march 21st to January

1st, and so this calculation method should not be used for dates before

this changeover. - Unfortunately, not everyone agreed to the change

at the same time. The change was in fact officially enacted in 1582, but

only some catholic countries actually did change at this time. After this

other countries took their time before accepting the change. Great Britain in 1752, Japan in 1873 and China (the last) in 1949. In

several cases, such as Germany,

only some regions changed at a time, and Sweden removed the days one by

one over a long time. - The overall result of this is that for

centuries, each country had its own system, and dates did not fall on the

same day. if you are looking at a date, you need to take into account if

it was before the changeover in that country, and take into account the 10

(or more) days removed from the calendar, the fact that the years used to start on a

different day.

Shortcuts

There are several shortcuts that can

be used to simplify and speed up the process so that you can calculate the

result almost immediately.

·

When working out

the year, remember that as the

calendar repeats itself every 28 years within each “century”, we can subtract 28 or multiples of

28 (56 or 84) so it is easier to add a quarter on to the year if it is a

smaller number. Therefore 1996 is the same as 1996-84 =1912. It is much easier

to add a quarter of 12 onto itself, than a quarter of 96. In this way, the

greatest number you will have to work with is 27.

·

When the year is a

multiple of 4, such as 16, it is very easy to add a quarter (16/4=4

16+4 =20.). Some people may have problems when the number is not a multiple of

4. (e.g. 27/4). Because we do not need the decimals in the result, the easiest

and quickest way is to take the nearest multiple of 4 below the number, and

calculate a quarter of that, adding it onto the year. (e.g. 1927: the nearest

multiple of 4 below this is 24. 24/4=6. add 6 to 27 to get 33.) Many people may

find this easier than working out the division and then eliminating the

decimals (27/4=6.75. eliminate the decimals to get 6. add 6 to 27 to get 33)

·

It is good

practice to subtract 7 or multiples of 7 at this point rather than adding on

the month and the day before doing it. The same is true for the day. This is

because it is easier to recognize and subtract multiples of 7 from smaller

numbers.

·

Simply remembering

the final year code for the current year and the coming year makes instant

calculations possible, as calculating the year code is the time-consuming

process. For the years 2000-2003, the numbers

correspond to the last digit of the year. This is a very quick method.

Examples

The thought process for a date such as

20/12/1967 should be as follows: (explanations are in parentheses)

67- 56 = 11 |
(Take multiples of 28 from |

11 + 2 = 13 |
(Add a quarter of the |

13 – 7 = 6 |
(Take away 7 or multiples of |

December = 4 |
(The code for the month from |

20 – 14 = 6 |
(Take away 7 or multiples of |

6 + 4 + 6 = 16 |
(Add the codes for the year, |

16+1=17 |
(Add 1 if the date is in the |

17 – 14 = 3 |
(Take away 7 or multiples of |

3 = Wed |
(The final number indicates |

For a date in

2000, 2001, 2002 or 2003, remember that the year code is simply the last digit,

so for a date in any of these years, we already know the year code.

So, to work out a date in 2000, we

forget the year code: for example 4th August 2000

August = 1 |
(The code for the month) |

1+4=5 |
(Add the codes for the month |

5 = Friday |
(The final number indicates |