When you're in school, they aim to teach you a basic level of education designed to provide you with the skills you'll need in later life. Well, I can honestly say, they got it wrong. I don't think I've ever used Tan and Cosine in a calculation since I left school. I've used πr2 to work out the area of a circle, I may even have used Pythagorean theorem for working out the area of a triangle. Most of the other equations and theories were left behind though, in fact, I've never had need of a scientific calculator at all since leaving school.
So what are the sort of skills you'll need in real life? Well, some of the ones I seem to have used no matter what job I was doing were learnt in primary school. Cutting and pasting are a real life skill, practice them all you can and, kids, the next time your teacher is trying to tell you the necessity of learning quadratic equations, slap a piece of sticky paper over their mouth (cut to shape, obviously).