Archive for August, 2012

Aug 28 2012

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How to become a Walking Calendar

Walking Calendar Revised
What day of the week is that?

Now you can know in seconds without a calendar.  Remember 4/4 (April 4th), 6/6 (June 6th) 8/8 (Aug 8th), 10/10 (Oct 10th) and 12/12 (Dec 12th). These dates  are 63 days apart (9 weeks exactly), so they all fall on the same day of the week. This year it is Wednesday. What about February? Feb 28 (or this year is leap year Feb 29th) are 35 days (5 weeks) before 4/4 so it is on a Wednesday. Add that the Fourth of July is 28 days after June 6th is also on a Wednesday. Next year (2013) all these dates will be on Thursday. In 2014, all these dates will be on Friday, and in 2015, all these dates will be on Saturday. Cool!

Add the little jingle: “Thirty days hath September, April, June, and November” (all the rest have 31, except for February) and you can easily figure out which day of the week any date falls on for the next 3 years. Of course this is a perpetual system, so expand this for the next 2o-50 years if you so desire. Wow, numbers are cool friends!

Examples: Friends and Family birthdays and Holidays

For 2012 first: There are several ways to find each answer.

Feb 23: We know Feb 29 is a Wed, so it is six days earlier, a Friday.

Mar 17: Since Feb 29th is Wed, March 1 is Thursday, 16 days (2 wks 2 days) later would be Saturday.

April 9: Since 4/4 is Wednesday, 5 days later is a Monday (did you get it by going back two days?)

May 2: Since 4/4 is Wednesday, and 30 days in April, May 2 is the same day as April 32, 4 weeks later than the 4th, and also a Wednesday.

June 10: 6/6 is a Wed, so 6/10 is four days later, Sunday.

July 13: Fourth of July is Wednesday, so 9 days later is a Friday.

August 9: 8/8 is a Wed so it is a Thursday.

Sept 6: 8/8 is Wed and 31 days in Aug, so 29 (31-2) days later is a Thursday

Oct 13: Easy, we know 10/10 is a Wed this year, so 10/13 is on Saturday.

Dec  9: We know 12/12 is a Wed so 12/9 is 3 days earlier, a Sunday.

Christmas – Again 12/12 is a Wed, so 12/25 is 13 days later, also a Tuesday.

Jan 1, 2013 We know the 12 of Dec (2012) is a Wed and there are 31 days so Jan 1 (Dec 32nd?)  is 20 days later, a Tuesday.

2013 Birthdays and Holidays All days are one day later than 2012 dates, or you can figure them out (all dates (4/4, 6/6, 8/8 etc) are now on Thursday)

This Perpetual Calendar not a good fit for every kid to do a full follow through, but even if they play with 4/4, 6/6, 8/8 etc, they can have fun and have a structure for visualizing and learning math and calendars.

And a kid (or an adult) who gets fascinated with this is going to learn:

Practical math

Fluency in Addition, Subtraction, multiplication (by 7s)

Number of days in a year

Number of months in a year

Number of days in each month

Name and number value of each month

Week circle is 7 days so 5 days back is 2 days forward.

Pride in amazing adults and other kids at their skill

Practice visualizing a calendar and numbers

A useful tool that they can use the rest of their life.

They could also learn about:

Blue moon definition


Much more

Tricks: 4/4 in 2013 is a Thursday, so Feb 1 and March 1 will be a day later (Friday in 2013)

You can fascinate kids with this and then have them prove how  and why it works!  Enjoy!

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