I asked DD11 how things are going at school. She is in sixth grade but accelerated into the 'advanced' eighth grade maths class where they are apparently covering the Common Core's version of Algebra I. She had always complained that the girls don't really care about it and that the boys think that they know everything - but don't.
She related an incident to me during which she found that one of the teacher's answers was wrong, stuck to her guns and was able to show the whole class why her answer was correct - kudos to AoPS for helping her to distill a problem down and tackle it in the simplest way, btw.
What happened was that the class was covering rational exponents and was doing an exercise that involved pairing up with a partner with one person holding up a card with the expression on one side of the card and the answer being on the side facing the 'holder' of the card. They took turns.
The whole class noticed that DD was doing the calculations required in her head and this drew the attention of the 'lead boy' who had taken the class the year prior but had not passed it due to illness. Up to this point he basically knew everything already so was looked up to by the rest of the class.
He came over with a card that said 49^1.5 where the 1.5 was expressed as a vulgar fraction - 3/2. Right away DD saw that it was really 7^3 and announced that answer to be 343. Wrong! Declared the boy triumphantly and revealed the answer on the other side of his card - 243.
My DD patiently explained that the given answer was wrong. She said - look it's basically 7 cubed, which is 49*7, i.e. (50*7)-7. The boy and the teacher conceded that she was correct.
After sharing her account of the incident with me, my DD said:-
"They know why I'm there now!".
[DD's maths teacher this year, I have to say, is a gem. She has been extremely supportive of our DD and did not take it personally at all when DD found her wrong answer as some teachers might have done]
Last edited by madeinuk; 02/15/16 06:37 PM.
