I’ve always thought of it as the fraction 9/5 instead of 1.8. I think that makes it easier because you can break it down into two steps, dividing by 5 and multiplying by 9. can’t multiply by 9 in your head? well that’s easy, just multiply by 10 and subtract the original number. and dividing by 5 is just dividing by 10 and then doubling it.
(I really wish math education put more emphasis on breaking down problems into a series of smaller problems like this)
I’ve always thought of it as the fraction 9/5 instead of 1.8. I think that makes it easier because you can break it down into two steps, dividing by 5 and multiplying by 9. can’t multiply by 9 in your head? well that’s easy, just multiply by 10 and subtract the original number. and dividing by 5 is just dividing by 10 and then doubling it.
(I really wish math education put more emphasis on breaking down problems into a series of smaller problems like this)
Doesn’t “common core” kind of do that but parents complain?