The quickest way possible I need to revise because I haven't started and I have exams on the 18th
do the exam questions and if you don't know how to do something look in your book, ask a friend or ask your teacher
I would say do exam questions or go onto adaptemy.ie .It is an online maths site that lets you try out sums and if you get it wrong, it shows you the solution
As deedunny has already suggested doing exam questions is one of the best ways to revise maths. You can't revise Maths without doing Maths! If you get stuck, you can look at marking schemes, in your book or at some of the resources on studyclix to try and help you. If there's any specific Maths questions you want help with you can ask your teacher or here also. Just remember that revising Maths DOES (unfortunately) take time and effort and you do have to DO it, to understand it.
Hope that helps and good luck in your exams,