Talk

Multiplication griding woes,how are kids supposed to do it quickly in a timed test?

(7 Posts)
Kazooblue Tue 05-Mar-13 20:09:26

So DS 9 knows all his tables,new timed test are sums like

74
X46

He has to do 25 in 8 minutes and is tortuously drawing grids per question(making some mistakes because he can't read all his many calculations).

Is this right,or is there a quick way?

Haven't taught him the way I was taught as don't want to teach the wrong way to school but I was seriously tempted tonight,would be soooooo much quicker!

When are they bringing the old way back,read somewhere that it was possibly on the cards?

Kazooblue Tue 05-Mar-13 20:10:27

Sorry that would be gridding!

Kazooblue Tue 05-Mar-13 20:17:12

Actually the ones he is having real problems with are like 314
X33

Kazooblue Tue 05-Mar-13 20:19:04

314
X33

DeWe Tue 05-Mar-13 20:42:59

Tbh I just taught dd2 the old method.
She had 4 sheets of 20 each of those to do. She did the first sheet the grid method. Took her an hour, with about 75% accuracy, mostly silly errors in adding up or forgetting to multilpy by 30 rather than 3.

So I showed the the old method. Despite being tired by this point, she then did the other three sheets in 10 minutes total with 100% accuracy.

bangwhizz Wed 06-Mar-13 11:36:40

I calculate that to be just under 20 seconds for each one?
I have just timed myself doing 314 x 34 by that method and including all the writing out and the adding up of numbers in the grid it took me 40 seconds. I am a qualified accountant so reasonably numerate

learnandsay Wed 06-Mar-13 11:53:49

I didn't know what gridding was so I had to look it up here: www.mumsnet.com/learning/maths/grid-method-explained there are more steps than with the old method. I guess (unless you make a mistake) one advantage over the old method is that you don't have to remember to add zeroes beneath the sum when multiplying by ten or more. But, if you don't forget the zeroes, the old method is simpler and easier to sanity check.

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