Most students in high school would rush and get a pencil or pen and write the equation if they see word problems such as Problem 1. I’m sure many of you will do the same. But you should really stop wasting lead and ink because problems such as this can be solved mentally.
Many are poor in mental math because most of us did not develop the habit of solving the problem mentally first, before getting a pencil and paper. Most of us, and our high school teachers too, are so obsessed and always in a hurry to write “let x = something” when we see word problems. If you want to be a good problem solver, the pencil and paper (and other tools) should be the last resort. Before getting a tool, try solving any problem in your head first.
Before you get excited, take 3-5 minutes to solve Problem 1 in your head and see if you can get the right answer before you continue reading. » Read more