Measure the Earth: Useful Links

To find the latitude of your position:

To convert your latitude to a distance measurement:

  • GPS Latitude and Longitude Distance Calculator
    Enter your latitude, but enter 0 (zero) for longitude. Then enter 0 for both latitude and longitude for the equator. Click to calculate your distance to the equator in meters, km, feet, or miles.

[I will also add these to the original post.]

Math Project: Measure the Earth

Tomorrow, September 23, is the equinox — when night and day are equally balanced (or would be, if the sun appeared as a point, rather than a disc). If we lived on the equator, the sun would appear directly overhead at noon and would cast no shadow. Therefore, it’s a great day to perform Eratosthenes’ experiment of measuring the earth:

Continue reading Math Project: Measure the Earth

Sept-Oct 2010 Math Calendars

As I was preparing for Wednesday’s Homeschool Math Club Games & Activities meeting, I remembered my old math calendars and thought, that would be a fun activity to offer. So I pulled up the files and discovered that the days of the week matched perfectly. What a cool coincidence!

So in case you missed the math calendars last year, or in case it’s been long enough that your children have forgotten, here are the “new” versions:

Addendum

Umm Ahmad created an easier version for young students:

Continue reading Sept-Oct 2010 Math Calendars

Planning a New Math Club

[Photo by Waponi.]

A few years ago, I had several (potentially) future engineers in our homeschool math club, and we enjoyed the challenge of MathCounts and AMC puzzles — but the current crop of local homeschool students is another story.

Last year’s contest-based club meetings dwindled to one student. Even before the recent MathCounts rule changes, I knew I needed a new plan. The final straw was Kitten, whose moaning complaint that she “hates math” has begun to drive me crazy.

So, what’s a homeschool math teacher to do?

Continue reading Planning a New Math Club

How to Start an Argument: The Monty Hall Problem


[Photo by MontyPython.]

You can get a good argument going in almost any group of people with the infamous Monty Hall problem:

Imagine you are on a TV game show, and the host lets you choose between three closed doors. One of the doors hides a fancy sports car, and if you pick that door, you win the car.

You pick door #1.

The host opens door #3 to reveal a goat. Then he gives you a chance to switch your door for the unopened door #2.

Should you switch?

What if you say you’re going to switch, and then the host offers to give you $5,000 instead of whatever is behind door #2?

Try the game for yourself at the Stay or Switch website.

Continue reading How to Start an Argument: The Monty Hall Problem

Math Clubs, Math Circles, and the Richmond Math Salon

Photo by jaaron via flickr.

If you’ve been thinking of starting a math club, here’s a good model:

People have this notion that math is about getting a right answer, and the testing really emphasizes that notion. And that’s such a bad way to approach math because it makes it scary.

When you look at little kids, they pose their own questions. They say, “Ooooh, what’s bigger than a million?” And they think about things their own way. At school, the teacher poses the questions, and the students answer their questions. Schooling is not a natural environment for learning.

— Sue VanHattum, Math Mama Writes
Richmond Math Salon: A Sweet Sampling

Continue reading Math Clubs, Math Circles, and the Richmond Math Salon

20 Best Math Games and Puzzles

[Photo by fdecomite.]

UPDATE

See the new, expanded games post here:

Original Post

Over the years, Let’s Play Math! blog has grown into a sprawling mess of 480+ posts, which can make it very hard to find the specific math tip you’re looking for. The Archives page is nearly useless, with the articles organized by month of publication.

Therefore, I’ve begun putting together a Best of the Blog page, collecting the all-time favorite blog posts from each category. [It’s done! :D]

And where better to start than with my top hands-on activities?

Skim. Click. Explore. Have fun!

Continue reading 20 Best Math Games and Puzzles

Game: Target Number (or 24)

[Photo by stevendepolo via Flickr (CC BY 2.0).]

Math concepts: addition, subtraction, multiplication, division, powers and roots, factorial, mental math, multi-step thinking
Number of players: any number
Equipment: one deck of playing cards (face cards and jokers removed), pencils and scratch paper, timer (optional)

Set Up

All players must agree on a Target Number for the game. Try to choose a number that has several factors, which means there will be a variety of ways to make it. Traditionally, I start my math club students with a target of 24.

Shuffle the deck, and deal four cards face down to each player. (For larger target numbers, such as 48 or 100, deal five or six cards to each player.) The players must leave the cards face down until everyone is ready. Set the remainder of the deck to one side.

Continue reading Game: Target Number (or 24)

Battlestations!!!

Nerds battle hungry football players who want to eat their giant fractal Dorito creation:

For more details on this video (and photos of the fractal’s construction), check out the Blown Apart Studios page. I’m looking forward to their next project, Nerd High, a musical comedy set in an alternate reality where nerds rule the school and jocks are the outcasts.