Jonathan Groves
Posts:
2,068
From:
Kaplan University, Argosy University, Florida Institute of Technology
Registered:
8/18/05


Re: RE: Teaching Dev Mathematics Conceptually: practical ideas
Posted:
Feb 9, 2009 10:44 PM


> > 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.

