So, I understand that the number line is a way to conceptualize relational distances between numbers, but in that example I’m struggling to see the relation between 57 where the line ends and 111, the answer. If you have insight, do you mind elaborating?
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dandelion@lemmy.blahaj.zone 5 days agosort of like the reactionary trend of pulling your kids out of school because Common Core is putting emphasis on teaching math in conceptual ways rather than just by rote memorization?
Squirrelanna@lemmynsfw.com 4 days ago
Lyrl@lemmy.dbzer0.com 3 days ago
I think they were trying to demonstrate the second type of dot should be increments of 10 - the missed step in the original answer - and both messed it up (started with an increment of 20 as you pointed out) and extended it way beyond what was required for the problem at hand.
Squirrelanna@lemmynsfw.com 3 days ago
Okay at least I know I’m not just going senile trying to interpret this haha.
Droggelbecher@lemmy.world 4 days ago
I’m shocked that the US only adopted this in 2009. I’m pretty sure my mum, who went to primary school in the 70s, recognized number lines when I was taught to use them on 2005ish. I’m having a hard time imagining how else you’d explain it.
dandelion@lemmy.blahaj.zone 4 days ago
look, we work very hard on being reactionary here in the U.S., we’re a world leader in reactionary politics
ricecake@sh.itjust.works 4 days ago
First you make them memorize single digit subtraction X - Y where X >= Y. Then you extend that to small double digit numbers.
Then you teach “borrowing”. 351-213. Subtract the 1s column. Can’t take 3 from 1, so borrow 10 from the 5 in the 10s column, making 11 in the 1s column and 4 in the 10s.
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Definitely more clear, right?