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Nurturing the Years of Wonder
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lapazfarm
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Posted: Jan 25 2008 at 9:07am | IP Logged Quote lapazfarm
I am totally confused on how to use this. The addition board is simple enough, but I just dont get how the plain strips are used here.
Here is the description from MTC:
     Presentation: At a table, examine the board. Note the blue line. Introduce the wooden strips and build a stair with them. The wooden strips are placed vertically above the board from longest to shortest respectively placed above the numerals 1 to 17. The child builds the blue stair to the right of the board. Note: To take away, always begin with the largest blue strip, never record an answer in red. Point to the 18 on the board and ask the child to identify it. State that the blue strips are used to take away. They represent the subtrahend. Place the 9 blue strip on the board. Align it on the right, beginning with the number 18 representing the minuend and cover up the numerals along the top of the board with the plain wooden strip. The answer is found directly to the left of the blue strip. Write the equation, 18 - 9 = 9. Repeat using the next strip in diminishing order. The answer is in red, therefore, the child will not write down the equation. Move across the numerals on the board, from right to left, to locate the next minuend, ie. 17. We no longer need 18. Cover the numeral(s) with the appropriate wooden strip directly above the current minuend, ie. 17. Proceed as above. When the child reaches 9 as the minuend he may need some help as he will get zero for an answer, 9 - 9 = 0. When 8 is the minuend, tell the child not to record an answer where the blue strip goes beyond the left barrier of the grid. The child checks his work with the Subtraction Control Chart #1.      

So, do I use the plain strips to cover the numbers that represent the subtrahend, or do I use them to cover the numbers that are greater than the minuend? Or both?
I am confused.

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Meredith
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Posted: Jan 25 2008 at 9:31am | IP Logged Quote Meredith
OK, what we have done is use the white (or brown) strips to cover up the numbers at the top of the board. For example if your equation is 15-6 then you would use the white strip that is sufficient to cover up from 18 to the 15, then you place the blue 6 strip (in the boxed area) from the 15 to the 9 to get your answer of 9, make sense??

My page on this is from the Shu-Chen math album!

HTH, Love,

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Mackfam
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Posted: Jan 25 2008 at 9:39am | IP Logged Quote Mackfam
Oh I just re-read about this in Lillard's "Montessori in the Classroom" - she explains how she uses it.

I see Meredith has already popped over to offer the explanation though. I can try to re-iterate what Lillard says, but I'm off to the doctor, so I'll check back in when I get home. I'm betting several others will have offered sufficient explanation by then though.

My son didn't care for the subtraction board, preferring instead to just keep using the addition board. I'm sure we broke every rule of Montessori (except for the parent interference role ) I just let him use the board, and his method was very similar to the one outlined for the subtraction board. I was pleased that he was simply able to make the connection on his own.    Sorry, I know that wasn't much help.

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