I received a few emails from parents recently wondering how to help their children get better in math. Parents often apologize for not being strong at math themselves, and the students, in my case all teenagers, have trouble communicating with parents about, well, a lot of things, let alone math. Creating a genuine way for children and parents to communicate with each other about math has always been difficult. Thankfully, tools like Wolfram Alpha can come to the rescue.
Here is the advice I gave one parent this week whose child is learning to factor quadratic trinomials:
Think of four numbers, keep them between 1 and 8. For example, 2, 1, 5, 7.
You can then write them like this: (2x+1)(5x+7) or make some negative: (2x - 1)(5x+7).
Give the top one (10x^2+9x-7) to him, and say to factor it. A groan at this point is natural. And then he will remember how to do it. The final answer should be the same as what you entered into the website. You can come up with new numbers and do this as much as you want - it will only make him stronger. If he has trouble, make the 1st and 3rd numbers you pick be 1, and it will simplify it a bit.
Yes, it will result in at least some expression of teenage 'come-on-mom/dad-ery'. But that's probably going to happen anyway, right?