I went back to school, and had to finish off my math.
The professor wanted me to do the math on paper her way which was pathetic.
I told her that this could be done in your head, but no she said it had to be on paper to show how I got the answer, and then do it her way which was mind boggling.
For example , lets say this question I just thought of for an example.
If I ma 6 and my sister is half my age . When I am 70 how old is my sister.
Easy right. 67 you do it do it on your head, but common core wants you to put it on paper. Then double it multiple it, and carry it or something like that.
Just stupid.
I ended up telling the professor it was stupid and just left the class.
6 is pretty close to 10.
Half of 10 is 5.
But you are only 6, so you had 4 more years in there.
But you just worry about half of those 4 extra years.
And 4 = 2+2.
So 5-2 = 3. So your sister is 3 when you are 6.
Now I’m not going through all of that B.S. again (and yes - that is how my kids were taught!) We also worked at home so they could do it the regular way. My one daughter could not do the common core way no matter how hard she tried. We finally met with the teacher and told her that if she got the right answer that was good enough for mom and dad.
Anyway - the answer of how old your sister is when you are 75 and she is half your age - she is 32.5! ;)