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Advanced Academic Programs (AAP)
Reply to "Is there a benefit to teaching “old math”?"
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[quote=Anonymous][quote=Anonymous]OP here. For example, if I have to multiply 65 * 32, I write it vertically on paper or do it vertically in my head. 65 X 32 ——- 130 + 1950 ——— 2,080 But my kid does the distributive property breaking down the 65, etc. He doesn’t know how to do it the old way (above), so I am thinking of teaching him but not sure if it is worth it.[/quote] Think about the problem a bit and you realize that 65 is a multiple of 5, and 32 is a power of 2. So you do: 65 * 32 = 13 * 5 * 2 * 16 = 13 * 4 * 4 * 10 = 52 * 4 * 10 = 208 * 10 = 2080 People trained in the "old ways" use the vertical math only if their 2-second check doesn't find a faster way that maps to already memorized facts. You basically rearrange prime factors in ways that map to already memorized facts like '13 * 4' (4 suits in a deck of cards), or obvious ones (like 52 * 4 = 208). Or is that the "new way?" Doubt it. [/quote]
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