Wednesday, May 14, 2008

Hey, you can't take the blocks home..or can you?

My students in grade 3 are learning how to do subtraction with some regrouping. One of my students came to me and said he needs help understanding his 1's, 10's and 100's. He was using base ten blocks, (click here to see a picture from a math supply store if you don't know what base 10 blocks are)

So I got some advice from a friend of mine about finding some good math sites on line, and she referred me to this site:

It covers a lot of different grades, but requires that the teacher play around with it first. I especially liked the base ten blocks exercises for teaching adding and subtracting with regrouping. When you use base 10 blocks in the classroom, students need to exchange 10 one's for every stick of 10 when doing regrouping (carrying or borrowing). On the National Library of Virtual Manipulatives, the stick of 10 blocks come apart before the children's eyes, so they can see what it really means to borrow from the 10's column when doing subtraction.

I just can't do it justice with words. Go to the site, and try it yourself. I don't think it need replace the blocks, however before introducing the topic of regrouping with base 10 blocks with the actual blocks themselves, I would consider doing it virtually. Try it yourself; this is one of the times I would say I like the virtual manipulative as much as I like the real deal.

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