Ok, this isn’t actually a treatise, but it is his explanation (swiped from the comments of the Weekly Reviewins I posted today) of how he uses the abacus with Tank. I’ve had several people ask me how we’re integrating the abacus, but I’m not the one doing it, so I had to rely on Officer Daddyman to betray his secrets. Since not all of you read all of the comments, I thought I’d post it here for your enjoyment:
The abacus I bought for Tank has 2 rows each of 5 different colored beads (blue, green, red, yellow, tan). We started by just using the blue beads to count to 20, as well as writing the numbers on the dry-erase board. About two weeks ago I started writing some simple addition and substraction problems on the dry-erase board, Tank would use the abacus to find the answer, and then he would write the answer on the dry-erase board.
Last week we used the green beads to count by 10’s, and wrote that sequence on the white board. We then did simple addition problems using multiples of ten to illustrate how the tens and units place combine in written form and with the abacus. For example, we would write out 20+2=22 and he would count out 22 on the abacus.
Today we ventured into subtracting from numbers greater than 20. First we practiced substituting 10 blue beads for 1 green bead, and vice versa. Next, I wrote down some subtraction problems on the board with numbers greater than 10, and we practiced starting with a green bead and exchanging it for 10 blue beads to facilitate the arithmetic. The final problem (his Challenge problem) was 30-14. He was a little confused at first, so I re-wrote the problem as 30-10-4. He understand that no problem. We started with 3 green beads and he took away a green bead (10) and then exhanged a green for 10 blue to subtract the 4.
When I told him how well he did with subtraction, and that he even figured out the Challenge problem, he said “I know! That’s what’s making my mind get bigger!”
The abacus is a great tool, and I have the advantage of first learning arithmetic using one. I used poker chips to teach Cpt. Science about odds and ratios. I highly recommend Texas Hold’em for those concepts.
