Of course, that's the ``right'' way to add fractions. Used much more frequently than the mathematicians' way. Batting averages (cricket or baseball), bowling averages (cricket), grade point averages, ... Both should be taught and carefully distinguished! R. On Tue, 26 Apr 2016, Warren D Smith wrote:
You can pick a or c: 6*(9*1) or 6*(9+0)
why not b too? 6*(7+2)=6*(2+7)
Not that I know much about educating children, but I suspect that demanding detailed educational standards about content is a waste of time. More effective might be to demand that the teachers actually know their topic. E.g. I had an elementary school teacher try to teach us that a/b + c/d = (a+c)/(b+d). Some parent, perhaps mine, later stepped in to try to correct her. So, maybe: don't test the children, test the teachers.
-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
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