Friday, August 20, 2004

Taking Away

I'm so irritated by post and comments on (Why do I read it? Same reason I listen to AM radio when driving across Pennsylvania.) Mostly they're making fun of a program without knowing any details. The University of Arizona has received a large grant to design mathematics curricula for Hispanic students that are relevant to their culture and community. I don't know about the School of Education at the University of Arizona, but their Math Department runs many well-respected programs to improve education, including one that involves Hispanic parents in their children's math education.

One thing the critics keep insisting is that addition is addition no matter what the culture. The same is not true of subtraction.

Let's take:

53 - 28

In the United States and Canada, we would solve it this way: You can't take 8 from 3 because 8 is bigger than 3, so you borrow a 1. Change the 3 to a 13 and the 5 to a 4. 13 minus 8 is 5, and 4 minus 2 is 2:

subtraction worked out

However, in Latin America and the Carribean (and in parts of Europe) it's done this way: You can't take 8 from 3 because 8 is bigger than 3. Change the 3 to a 13 and carry the 1, changing the 2 to a 3. 13 minus 8 is 5 and 5 minus 3 is 2.

subtraction worked out

You get the same answer, just in a different way.