## Friday, January 15, 2010

### Addition and the Part-Whole Circle

The other day Little Bean and I worked on addition up to 10 using the Part-Whole circle and tally marks. This Right Start lesson called for Little Bean to visualize the tally sticks moving from circle to circle so that he could easily solve problems up to 10 in his head (without the abacus).

Here is one of our problems: an addend goes in each smaller circle and then Bean needs to find the sum. 4 + 3 is not hard if he uses the abacus, but to do it in his mind he must visualize changing the problem into something he can understand more easily. Remember how Right Start teaches the child to think in terms of "5 and"? (5 and 2 is 7, 5 and 3 is 8, etc). This comes in super handy for doing mental math.

Here is where Bean's mind went to right off the bat: 4 + 3 is the same as 5 + 2 and 5 and 2 is 7! Therefore, 4 + 3 = 7. He decided to take away one of the tally sticks from the right circle and add it to the one on the left, giving him 5 and 2 as his parts. From there, it was a matter of recalling what 5 and 2 is from the very beginnings of Right Start Level A. I was SO impressed that Little Bean could do this in his head by thinking in terms of "5 and". We did many problems like this last week, and he loved them all. It was a fun challenge for him to answer my question, "What could we change in this problem so that we can solve it without counting?" He figured it out every time.

Here is the completed problem 4 +3 = 7. See how easy it is to see the sum without counting? Even if you don't purchase Right Start for your math curriculum, I highly recommend getting an AL abacus from them!

Raising a Happy Child said...

I am interested to see how math is being taught here in US. I completely don't remember ever seeing those strange circles when I learned math, but we did a lot of manipulatives (so, yes, counting with props). It sounds though that the system works well for Little Bean.

Mom with the best job in the world! said...

Wow! That is impressive! I was horrible at math (doing it in my head) still am. I don't want to pass that on to my kids. I will look into Right Start and the abacus. Did you get it through Right Start? Where did you order it from?
I am beginning homeschooling this fall with my son who will be 5 in December. Can you send me the website?