model method

I came across what may be a terrific web site for non-math majors trying to teach the Singapore Math curriculum the other day:

Teach Kids Math Using the Model Method

I could have used this site when I first started working through Challenging Word Problems Book 3 lo these many years ago. My knowledge of arithmetic was so fragmented at the time that I didn't immediately perceive the various "genres" of bar models. Each problem I solved seemed almost to call for a whole brand-new, never-before-seen bar model. (Not quite, but close enough.)

I needed a map of the world.

One of the blinding revelations that came to me via bar models was the reason for the word "difference" as in the expression: "Find the difference." It had simply never occurred to me that subtraction was two things (scroll down - may need to hit refresh a couple of times):

• how much is left when you take away "X"?
• what is the difference between two numbers?

The great thing about the "Teach Kids Math" site is that it lists "Comparison" on a separate button on the sidebar. You can take one look at that page and realize: nobody ever mentioned "comparison" back when I was in school.

I'm not so crazy about the way they draw the comparison model, though. In all of the Singapore books I've seen, they've drawn the comparison model the way I did (though the bars aren't "stacked" the way I stacked them...don't know why I did that.)

I'll probably have C. take a look at the site.