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?
Edit: actually… Aren’t the numbers they wrote in on the line WRONG? Why did they go down by 20 to 107, then by 10 to 57 arbitrarily? If you do 10 instead, then increment by 1 to 111… You get the answer. Did the person solve it wrong and put the right answer to get people outraged?
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.
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.
look, we work very hard on being reactionary here in the U.S., we’re a world leader in reactionary politics, and not teaching math well is crucial to keeping a vibrant slave worker population, otherwise they might start, you know, thinking for themselves
sort of like the reactionary trend of pulling your kids out of school because Common Core has changed how math is taught so critical thinking and conceptual understanding is incorporated, rather than teaching math by rote memorization?
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?
Edit: actually… Aren’t the numbers they wrote in on the line WRONG? Why did they go down by 20 to 107, then by 10 to 57 arbitrarily? If you do 10 instead, then increment by 1 to 111… You get the answer. Did the person solve it wrong and put the right answer to get people outraged?
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.
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.
Definitely more clear, right?
look, we work very hard on being reactionary here in the U.S., we’re a world leader in reactionary politics, and not teaching math well is crucial to keeping a vibrant
slaveworker population, otherwise they might start, you know, thinking for themselves