re: (Not Common Core)-- Why are they teaching math this way?

quote:

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Do you pull out the number line every time you add single digit numbers?

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If you're familiar with calculus, this argument should make sense. If you are not, I'll try to find another.


When asked to find the derivative of x^2, do you always pull out the limit as x-->a of x^2/x-a? The answer is probably still "no" much like in your scenario. But if you aren't familiar with how derivatives are calculated, you'll run into trouble when you get to more complex ones where the simple rule cannot be applied. A fundamental understanding of the simple aids in understanding the more advanced. Some kids learn that the number line can be replaced by their fingers. Some realize they can picture the number line in their head. Some then learn what addition and subtraction mean and can then go on go do it without any reliance on method because the concept is ingrained and simple to the point that it becomes automatic. But it really is all based on a number line.