1). State the problem in your own words. This makes sure you understand what is being asked.
2). Check assumptions. Are you guessing or did you get the assumption from the problem statement?
3). Calculate the answer, or hypothesize what you are expecting. Estimate the answer for example: 25 * 55 = about 20 * 50 = 1000
4). Evaluate your results. Does it fit, can you check the answer by plugging it back into the original equation?
5). Intepret your results. Do they seem to fit the original problem statement? Do you see something that is wrong and can you fix it?