## Wednesday, April 20, 2011

### Sets and Grouping, Part III

This blog reviews how we use elementary math in our everyday, grown-up lives.

Yesterday we grouped shirts by fabric type and pockets/no pockets. We were able to use Venn diagrams (overlapping circles) to demonstrate how items can be members of more than one set at a time.

Today, as you can see, we are looking at t-shirt colors. More specifically, how t-shirts can be grouped into sets, by color.

Notice that the primary colors (black, blue, etc.) are sorted alphabetically, not in "order of color."I have decided to group these colors using my own eyes, sensory perception, and color names that I like. If you are colorblind and/or have art training, you might divide the color groupings differently. You could use PMS colors, or some other color labeling scheme.

The middle column is men's shirt colors. I decided to contrast this by adding a right column with women's colors. Men can chose from t-shirts in these colors:
• 1 black
• 1 burgundy
• 3 browns (including camel)
• 7 blues
• 1 chamois
• 4 gray (including graphite)
• 4 green (including olive)
• 1 orange
• 2 red
• 1 white
Women chose from these colors:
• 1 black
• 2 brown (including mocha)
• 5 blues
• 1 gray
• 3 green
• 3 orange (including sienna)
• 1 purple
• 1 red
• 2 yellow (including chamois)
• 2 white (including natural)
Color designers make the choices in concert with the fabric manufacturers. Nowadays color choice is expected, and universal. Who could conceive of consumer products only offered in black and white?

But that's not always been the case - certain colors are more expensive, difficult to produce, harder to protect from fading, etc.I have neon-yellow, fluorescent-green and bright-orange emergency shirts that I keep in my car.

(If you're a long-time reader, you might remember the blog on (in)visibility. )

No doubt these are more expensive colors to produce, with limited appeal. I've noticed that Duluth no longer offers those yellow and green colors in t-shirts.

In math class, we often use color as an example of items that can be sort, grouped, or used to create combinations and permutations.

(If you can't recall the difference, you can go here to get our math glossary.)

I found an interesting resource for color lovers (and web page designers) put together by Mark at Techyuva. You can see how math very quickly gets mixed up with color... and you can download some color charts.

Many years ago we introduced this girl with the extensive wardrobe to our 3rd graders. Students calculate how many kinds of outfits she can create with her patterns and colors. See if you can spot some of her mis-matched socks... [click the image for a larger view)