Showing posts with label articles. Show all posts
Showing posts with label articles. Show all posts

Sunday, September 9, 2012

Math Reporting Fail?

http://www.patrickkphillips.com/2012/09/09/math-fail-same-retiree-magically-changes-ages-twice-in-same-story/

An opportunity to talk about underlying assumptions to word problems in a math class.  How old is she likely to be, and why do you think so?

Thursday, September 6, 2012

Thursday, April 12, 2012

Wobbly Table Math

http://www.scientificamerican.com/article.cfm?id=strange-but-true-turning&ref=sciam

It's a problem as old as civilization: the wobbly table. You may have thought your only recourse against this scourge is a hastily folded cocktail napkin stuffed under the offending leg. If so, take heart, because mathematicians have recently proved a more elegant solution. Just rotate the table.

Saturday, November 27, 2010

When Can You Reuse This Year's Calendar?

Let us first assume that you are only interested in which dates fall
on which days of the week; you are not interested in the dates for
Easter and other irregular holidays.

Let us further confine ourselves to the years 1901-2099.

With these restrictions, the answer is as follows:

- If year X is a leap year, you can reuse its calendar in year X+28.

- If year X is the first year after a leap year, you can reuse its
calendar in years X+6, X+17, and X+28.

- If year X is the second year after a leap year, you can reuse its
calendar in years X+11, X+17, and X+28.

- If year X is the third year after a leap year, you can reuse its
calendar in years X+11, X+22, and X+28.

Note that the expression X+28 occurs in all four items above. So you
can always reuse your calendar every 28 years.

But if you also want your calendar's indication of Easter and other
Christian holidays to be correct, the rules are far too complex to be
put to a simple formula. Sometimes calendars can be reused after just
six years. For example, the calendars for the years 1981 and 1987 are
identical, even when it comes to the date for Easter. But sometimes a
very long time can pass before a calendar can be reused; if you happen
to have a calendar from 1940, you won't be able to reuse it until the
year 5280!

Source and for more info:

http://www.faqs.org/faqs/calendars/faq/part1/