## Wednesday, September 23, 2009

### The Ten Triangle

In the picture above,Little Bean is using the AL abacus that came with the math kit from our Right Start curriculum. The AL abacus is unique in that each row divides the set of ten beads into 5 and 5. Each row has 5 blue beads and 5 yellow. This helps the child to see numbers 6 through 10 in terms of "5 and" (5 and 1 is 6, 5 and 2 is 7, etc). And if you don't use Right Start, but like this abacus, I was just at CM School Supply the other day and saw that they actually sell this abacus right in the store! Of course you can also purchase it from the Right Start website as well.

Another unique way to see numbers (specifically the number 10) on the AL abacus is to make ten triangles. You can see Little Bean has completed a blue "ten triangle" and is about to complete a yellow ten triangle in the photo above. Making the ten triangle is just another way to "see" ten on the abacus. Ten is whole line of beads, ten is 5 blue and 5 yellow, but ten is also a ten triangle. Little Bean made as many ten triangles as he could, and then we counted how many tens we saw on the abacus--ten tens, or 100 beads (eight were ten triangles and two were two lines of 10 beads each).