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If they wrote $5.55, they deserve the full credit. I do arithmetic admittedly weirdly in my head. I can't do arithmetic very quickly. When faced with $20 - $14
by minot 12y ago
If they wrote $5.55, they deserve the full credit. I do arithmetic admittedly weirdly in my head. I can't do arithmetic very quickly.
When faced with $20 - $14.45, I round up the $14.45 to $15 and subtract from $20. I have $5. Now, I think how much more I still have and that is $0.55. I add them together to get $5.55.
If I can write the answer, why would you dock points just because my way of doing this simple math is inefficient?
- rayiner 12y agoBecause the answer doesn't matter. If you just need the answer you can use a calculator. The point is to help kids develop an intuition for how numbers work.
- harryh 12y agoThe way you described calculating change is essentially the method taught in common core. Common core is not about efficiency, it's about helping kids develop an intuitive understanding of how numbers work. It turns out that a lot of children who learned how to subtract on paper with borrowing never learn how to do math in their head the way you described. Common core is an attempt to correct that deficiency.