Suppose you are going to Boston, and you 1 the city before. If someone 2 you about the interesting places in the city, you like to get some ideas of what you will see. But don't have a clear idea of where these places are or how to find 3 . However, 4 someone has a map of the city and 5 you the main roads and buildings, you may say, "Oh, now I see. I can find my way with no trouble at all." Working in math is somewhat like trying to find your way to a new city. Perhaps the words may tell you some information and you have 6 it, but you can't see any clear road 7 the answers. Maybe you 8 a kind of map of the main roads in maths 9 you find your way. Explore what lies in maths, and try your best to find the main roads. They will 10 you to the answer. If you can find the "map",the maths problems will be easily worked out.