Understand
Read the problem carefully.
What facts do you know?
What do you need to find out?
Is enough information given?
Is there extra information?
Plan
How are the facts related to each other?
Plan a strategy for solving the problem.
Estimate the answer.
Solve
Use your plan to solve the problem.
If your plan does not work, revise it or make a new plan.
What is the solution?
Check
Reread the problem.
Does the answer fit the facts given in the problem?
Is the answer close to my estimate?
Does the answer make sense?
If not, solve the problem in another way.