Just to let you elementary people know, I used the idea of fact families with my sophomores the other day. We've started Trig, and it's not uncommon to have an equation like sin 36 = 12/x. I explained to them that it's a real pain to have a variable in the denominator. Then I reminded them of their fact families: how if 2 = 6/3, then 3 = 6/2 because 2(3) =6. As a result, they could rewrite the original equation as x = 12/sin36, and simply take out their calculators. So, to all those teachers who did a great job of teaching their kids to internalize the basics, I offer you my thanks.