It would appear that while many parents have been homeschooling their children during the Coronovirus lockdown, no-one is teaching Pythagoras' Theorem.
So, in order to right this small, but not insignificant, oversight, here it is:
In a right-angled triangle:
the square of the hypotenuse is equal to the sum of the squares of the other two sides.
The other advice for children is:
By the time you leave school:
the job you want will be being done by robots
the girl you fancy now, will not be who you end up with
Also, if you don't do your homework, you might end up bitter, twisted, and regretting all of the things you didn't do.
Obviously, I don't know anything about that type of thing.