I don't know how they're used in C, but I think the only reason that it uses cards instead of 3D manipulatives is for cost savings. I think that whenever possible, the 3D manipulatives are superior.

We had the cardboard abacus tiles (showing 100) that come with level E, which we assemble into 3D models. My son crushed them to bits on the very first lesson.

I bought some wooden Montessori hundred-tiles instead. They work much better. I haven't bought a 1000-cube yet, but I would like to, and very well might when my daughter gets to the point of learning about 1000s.

For 10's, I made wooden Montessori-style bead bars, expect I did them with 5 and 5 in two different bead colours. I also made a couple sets of beads showing 1-9, also using "5 and x" colours.

You could use Montessori golden bead equipment for any of the amounts as well -- the 100's golden bead square and 1000's cube are really cool. Rather than just being the right size, or showing pictures of 10x10 dots (like the 100-tiles I have), there are literally, physically, 100 and 1000 beads strung together. If they weren't relatively expensive, I wouldn't be at all surprised if RS used those instead.

Actually, I think it would be great if RS sold these as a 'deluxe' option on the website...

Dawn,

Thank you for your message. You bring up an interesting idea and I did mention it to Dr. Cotter just to see what her thoughts were.

She said, "The Base-ten Picture cards are used to add 4-digit numbers together with trading (see Lesson 35 in Level B). The biggest problem with the set of the set of blocks is that they contain only 1 thousand and 10 hundreds, but 9 thousands and 27 hundreds are needed. The pictures also are another step toward abstraction because they are the same size just as the digit representing 7 hundred is the same size as the digit representing 7 ones."

I hope this helps, please let me know if you have any other questions.

Make it a great day,

Cassie
Activities for Learning-RightStart™ Mathematics
Cassie@ALabacus.com
www.ALabacus.com

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