Tuesday, January 23, 2007

Re-grouping in Math

My oldest dd is now a pro thanks to Singapore and Rightstart Math at regrouping in addition. But now we are on to subtraction. The concept of borrowing is not that hard it is remembering that we need to borrow.

To get through this little snag we are doing a section of problems each day from the Singapore text on a whiteboard and then using the Rightstart practice sheets on subtraction to practice our facts. I can see that we are making progress and by the end of next week she should be able to do the problems in the workbook on her own just fine.

I have been walking her through the problems. Here is our process:

1. I write out a problem on the white board and ask her: Is it addition or subtraction?
2. I put the larger number on the Rightstart abacus with separate lines for hundreds, tens and ones.
3. I ask her where we start and she points to the right column.
4. I ask her is there enough ones on top to give away the bottom number of ones?
5. If there are not, we then ask the tens if we can have some ones. She then marks out the ten making it the next number down and makes the one into a larger number.
6. Then we move to the next column and so on until it is finished.

Sometimes these steps can be tedious but it is getting the job done.

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