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Q&A #476 |
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This is explained in the text I used for a math methods class. The text is Guiding Children's learning of math, by Kennedy and Tipps. I used the 5th edition in 1992, so there may be a newer edition since then. In that text they say the contact for this product is: Touch Learning Concepts,Inc. 104 Manitou Ave. Manitou Springs, Colorado 80829 Basically, the idea is to use points on the numbers to count as you add or subtract. 1 has one point at the top 2 has a point at the top ( the beginning) and the bottom (the end works, or the beginning of the horzontal line) 3 has three points at the ends of the three lines 4's points are the top two points, and the other two right below them (they don't close the top of the four) 5's points are the two top points, the juntion where the curve starts, halfway around the curve, and the end of the curve 6 has two points at the top of the curve, two in the middle of the figure, and two at the bottom of the curve 7 has two on the top line, three in the middle, (one on each side of the vertical line, and one on the line) and then two more at the bottom 8 has three at the top, two in the middle, and three at the bottom 9 has three at the top, three in the middle, and three at the bottom. So if you were adding 2 + 3 you would count "1, 2" for the two, and then count on "3, 4, 5" for the 3. If you were subtracting 3 from 5 you would count "1, 2, 3, 4, 5" for the 5 and then count off "4, 3, 2" for the 3. There is another set of algorithms you might be interested in looking into. They are Hutchings Low Stress Algorithms , and can be found in the text mentioned above, and the 1976 yearbook for NCTM, Measurement in School Mathematics. -Gail, for the Teacher2Teacher service |
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