(01-16-2015, 05:16 PM)Naunet Wrote:(01-16-2015, 05:13 PM)MadWater Wrote: As a 27-year-old aerospace engineering student, many of the Common Core math methods are exactly how I do mental arithmetic.
I meant more the whole physically drawing out the number line thing. But yes, even I do the "subtract multiples of 10/100/1x to get closer to the answer" thing in my head a lot.
Well that's just so you have something to grade =P. You're effectively mentally drawing out a number line though. It's much handier than the "old school" subtraction algorithm, which is far less convenient and far more prone to error if you can't actually write it down. As adults, with simple calculators costing about 14 cents (which are only necessary if you don't have any kind of electronic device), pencil-and-paper methods of doing arithmetic problems are kind of pointless, imo.