Jonathan Groves
Posts:
2,068
From:
Kaplan University, Argosy University, Florida Institute of Technology
Registered:
8/18/05
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Re: RE: Teaching Dev Mathematics Conceptually: practical ideas
Posted:
Feb 9, 2009 10:44 PM
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>
> Regarding "PEMDAS":
>
> I once had a student from Africa who would use
> "BODMAS", which puts brackets first, then
> "oxponents," then division and then multiplication.
> I notice that if you do all divisions before all
> l mutliplications, it is actually equivalent to doing
> all multiplications and divisions in order left to
> right.
>
> Example: 15 * 12 / 3 = 15 * 4 = 60; 15 * 12 / 3 =
> 180 / 3 = 60.
>
> But, it is not always more convenient this way:
>
> 16 * 5 / 8 = 80/8 = 10 is more convenient than 16 * 5
> / 8 = 16 * 0.625 = 10.
>
> Just FYI!
Interesting way to look at the usual order of operations. I don't know if I had seen this before or not.
Doing all divisions first then multiplications is equivalent to doing multiplications and divisions in order from left to right isn't hard to see; it follows from the definition of multiplying fractions.
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