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Q&A #19033


"Carrying" in addition

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From: Ralph (for Teacher2Teacher Service)
Date: Nov 25, 2007 at 08:47:23
Subject: Re: "Carrying" in addition

Dear Priya, Thank you for writing to T2T. It sounds like your daughter has very good number sense, so she might find ways to solve 28 + 17 that are different from the so-called "traditional algorithm" [that we sometimes forget is only traditional in Britain and North America :) ], and hopefully her teacher is flexible enough to allow her to solve the example in her own way: So, for example, she might think of 28 + 17 as 20 + 10 , and 8 + 7, 20 + 10 is 30, and 8 + 7 is 15, she might be able to do 30 + 15 in her head, OR might break it down further into 30 + 10 + 5, or 40 + 5 = 45. All the "carrying" part of the traditional algorithm does is what your daughter "thinks" when she's doing "10 jumps". 1 2 8 + 1 7 ---------- 5 (thinking 8 + 7 is 15, which is 10 +5 so I'll put the "10" with the other "10s" I have to add) 1 2 8 + 1 7 -------- 4 5 (thinking: adding the "10s", I have 1 ten + 2 tens + 1 ten, or 4 tens, which I write as a 4 in the tens place) Hope this helps, -Ralph, for the T2T service

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