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.
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
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.
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.
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 themselvesFirst 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?