[Potironette]

In my opinion, ideally, they teach basic subtraction and that common core sort of way for mental math. Like "here's how to do it fast on paper" then, "here's a way to think about it in life but not on paper." I was taught normal subtraction and..that common core technique reminds me of learning mental math (but I wasn't good at that and we didn't focus on it too much so I don't really remember too well).
I don't really know what common core is though. I think I was in 5th or 6th grade when it was first implemented (that's 2010 I think). And then in 7th grade I went to a school that could care less about state/national standards.



Momentum is proportional to energy..? Is it related to change in momentum over time equals change in KE over distance (I remembered this as a part of some problem on my test..is it related?)? Oh, is that say, we don't know if an object of a higher temperature influences momentum? Err, I hear about dark matter on occasion but what is that?

Something about Newton's 3rd law was shown on the test--but I didn't remember what law no. 3 was. I can understand that explanation but, using Newton's first law, I'm not sure how it's different from the 3rd law..? Internal forces don't count as an outside force and the internal stuff technically moves but overall the object doesn't move anyway and so it doesn't influence the momentum?