One of the hardest things to do is realize that when your kid takes a math class above 6th grade, they're learning a foreign language. They have different uses for words - in effect, a whole new vocabulary. They have to learn new ways to deal with the skill set. After all, this is numbers, letters, new symbols, and sometimes new words that are symbols and expressions unto themselves!
One of the hardest yet easiest skills is trigonometry. It's the study of ratios of sides, relating angles to slopes. It sounds really difficult, and when they're first learning it, it IS. But once they've got the pythagorean theorem down, and the basic trig identities of Sin/Cos/Tan (better known as SOHCAHTOA to many), it's all just the same thing over and over again.
The hard part is that this means drawing, letters, numbers, and phrases. Sin 30 doesn't mean a sin as in bad, or 30 times. It means the ratio of the opposite side to the 30 degree angle as compared to the hypotenuse. Hence SOH. Sine angle = Opposite over Hypotenuse. And cos? Cosine, or the other side (co-sine). So Cos 30 means the ratio of the side that's not opposite the 30 (called adjacent, meaning right next to or touching) divided by the hypotenuse. Or CAH - Cosine angle = Adjacent over Hypotenuse. Can you figure out TOA now? I know you can puzzle out the O and the A. The T stands for Tangent, and just like it means in english (going off on one point neglecting the main issue), this means the ratio of the two sides that touch at the right angle, with the opposite one over the Adjacent one. The farther away topic divided by the one you're supposed to be on, if that makes any sense to you english people. :)
Anyhow, once you have those concepts down, and can identify which side is which, the rest of precalc and trig stuff is all easy from there.