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by coryrc 1841 days ago
999999*5 is far easier as 5000000-5 than 45+450+4500+...

Are you really arguing that the latter is faster and more effective to do in your head?

1 comments

Not at all. I didn't know we were discussing mental arithmetic.
Even on paper it's far simpler

(1000000-1)*5 => 5000000-5 => 4999995

Learning to find these patterns early sets up students for having an easier time with algebra later. Algebra is just rearranging equations. I don't understand, but students do struggle with going from "12/3=?" to "3*X=12 solve for X". We can't keep failing so many students every year and expect our country to hold together.