brownie Posted March 29, 2012 Share Posted March 29, 2012 required in long division without writing it out to the side? I haven't actually taught my kids this yet because it hasn't come up in any curriculum that I've seen but it seems like it should be time! e.g. 2820 / 47 = ? When you think the first number in the quotient is a 5, at what point should they be able to figure out the product of 47 and 5 is 236 without doing multiplication off to the side of the page? Brownie Quote Link to comment Share on other sites More sharing options...
5LittleMonkeys Posted March 29, 2012 Share Posted March 29, 2012 You mean 235.;) It depends on the dc in our home. One does it mentally by multiplying 40x5 and then 7x5; she's 12. The other one, who is 14, wasn't taught mental math when she was in ps so she uses a calculator. Dd9 will probably always do it with mental math because she has been taught mental math from the beginning and finds it faster. I personally don't mind them using a calculator for these types of side computations. I know that they know how to come up with the answers without the calculator. It is a tool to be utilized for convenience and speed...not a crutch. Quote Link to comment Share on other sites More sharing options...
redsquirrel Posted March 29, 2012 Share Posted March 29, 2012 I am guessing you are looking for an age younger than 40? I wouldn't try that in my head for fear of making an error. Of course, I can't go shopping without a list either. I actually require my son to write out as much as possible because he is prone to small errors in computation and by writing it out he can #1 check his mental math and #2 backtrack to find his mistake. Quote Link to comment Share on other sites More sharing options...
Karen in CO Posted March 29, 2012 Share Posted March 29, 2012 I still do it on the side of the page - it helps me to backtrack if I make errors and demostrate to my student what I did wrong. (I also shop with a list and still forget stuff on it. ) I don't think there's anything wrong with writing it out. I worked for years to get my dd to show her work and refuse to discourage that now. I fondly remember showing lots of work in college math and physics classes with the hope of getting partial credit for problems that I missed. Quote Link to comment Share on other sites More sharing options...
brownie Posted March 30, 2012 Author Share Posted March 30, 2012 OK maybe it doesn't get taught? It's something I do...and I don't actually mean I do it in my head. It's like I'm doing the multiplication out "sideways" using the number from the quotient and divisor as it's already written. I might write a carried number over the divisor as I'm doing it to keep track. hmmmm....Brownie Quote Link to comment Share on other sites More sharing options...
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