Friday, November 16, 2007

Dividing Conquered

Today my nine year old son taught me how to do something that I've had a mental block about for years. Something that, though I've always been good with numbers, slipped under the radar and which I never ever figured out how to do, even though I got my Maths O and A levels.

I confess I made it the whole way through school without knowing how to do long division properly. I knew a way of doing it that worked, but only if the dividing number could be separated out into single digit factors - like 24 into 6 and 4 - but I was lost if I needed to divide something by 23.

So when I realised that my son's class had started on long multiplication, I enquired if he was doing long division too. Today he came and kindly asked me if I'd like him to show me how to do it.

Armed with pencil and paper he asked for some numbers, with the proviso that the dividing number was a single digit. I called some out and he set to work on what looked like a fiendishly complicated series of workings for a single number.

I glazed over some of the explanation and, slightly disappointed that my problem with 23 wasn't about to be resolved, asked if it worked for 23 too. "Oh yes", he said and proceeded to work out the twenty three times table so that we could work the process through ….

Hurray! I finally know how to do long division, which should come in handy, if I ever need to work out how to divide 930 canap├ęs between my 23 guests and want to know how many will be leftover for me to scoff myself.

OK - they get 40 each and there are 10 left over for me and I didn't use a calculator!!

My son, on a roll after his teaching success, generously offered to show me how to do big minus sums too. I reassured him that I could remember how to do those. I don't want to sink too low in his estimation of my mental abilities, just yet.

3 comments:

  1. Can you send him over to give me a hand? My daughter sighs when she tries to help me... and has even been known to roll her eyes just a little, because I am so slow at my math and she can do great long algebra problems in her head.

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  2. Do you suppose there are different international codes for long division? Because I get the sense that you guys are doing it differently from me.

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  3. I also wonder if the way they are teaching it has changed... As far as I recall, the times table was not needed to do it the way I learnt! Probably the most useful thingk I learned in 12 long and painful years of maths at school was how to solve for x... But don't show me quadratic equation. Ever!

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