[quote=flu]
I am not against all of ccm…. But questions like this seem to beat around the bush of whether a kid really knows what a least common multiple is and overcomplicates explaining what an lcm is and how one goes about finding it.
The purpose of this question is suppose to challenge whether a kid knows lcm or not. But along with it, it introduces a lot of other things that while may be fine for some of us more mathematically inclined, will utterly confused he heck out of those that aren’t. For example, your average nonmath oriented kid is not going to feel that comfortable with fsomething like a function and variables. And now this questions overcomplicates the lcm lesson by introducing max(a1,a2), etc….and there’s a more practical consideration… When is such a “puzzle” type lcm question ever used in the real world, even in engineering and science… (It isn’t)…third.. This type of question will also make math incredibly more difficult to understand for those social-economically disadvantaged esl students by now introducing a heck of lot of English leaning language into a fundamentally easy math concept that should have been language agnostic. So… Again…I am not sure I understand the point of this type of question, except to see how well kids are at solving clever puzzle questions that have very little bearing on the real practical math use cases in the real world.
Anyway..my 4th grader figured this out, simple because her Chinese ol school math lessons taught lcm the old fashion way back when she was in 3rd grade and because she understands lcm now..simply because of practice practice practice.[/quote]
Sorry for the confusion. The language did not include the notation I used. The kids are supposed to think about the problem. OK, lcm(7, 9) is 63. However, lcm(a1, a2) is not always a1 x a2. So, when will that be?
I just liked the fact that you cannot simply drill the kid into applying specific algorithm to solve the problem.
