momtolgd Posted April 4, 2011 Share Posted April 4, 2011 Can someone please help me explain "WHY" long division works to my ds10? He is getting the "HOW" of it now, but wants to know "WHY." I am not too sure of how to explain it, so looking to all of you for some help. Thanks! Michelle :001_smile: Quote Link to comment Share on other sites More sharing options...
wapiti Posted April 5, 2011 Share Posted April 5, 2011 I don't know if this explanation will help, but my kids really enjoyed it http://letsplaymath.net/2010/04/12/the-cookie-factory-guide-to-long-division/ Quote Link to comment Share on other sites More sharing options...
Dana Posted April 5, 2011 Share Posted April 5, 2011 When we started it, I used base 10 blocks to show the place value and after doing the division with the blocks, I showed the algorithm. We did the blocks for a problem, then the writing. After a few days (yup), my son preferred the algorithm :) So for 892 / 3, you'd first divide the hundreds by 3 (show with blocks). We get 2 hundreds and have 2 hundreds left over. So we break the left over hundreds into tens. We have 29 tens. Dividing them by 3, we have 9 tens with 2 left over. We break those into ones. We have 22 ones. Dividing them by 3, we have 7 ones and 1 left over. Thus, 892 / 3 is 297 1/3. Showing with the blocks first really helped make the concept clearer. Quote Link to comment Share on other sites More sharing options...
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