Checking Math Solutions

Memorize this list of checking techniques:

1. Redo each step of your solution, but don't be satisfied with this.
2. Reread the problem.
3. In a word problem, picture the situation in your mind.
4. In a puzzle problem, try out your answer.
5. Redo with a quick approximation.

Why?

Redo each step of your solution, but don't be satisfied with this.

It's too easy to make the same mistake over again. Even if each step is correct, they could be linked together incorrectly. It is independent solutions that provide confidence.

Reread the problem.

Sometimes you plunge into the calculation and forget part of the question.

In a word problem, picture the situation in your mind.

Does your answer fit the situation?

In a puzzle problem, try out your answer.

A "puzzle" problem is one which asks you to find a number that meets certain requirements. You are learning effective techniques for attacking several kinds of puzzle problems. But the point of these problems is that the solution fits the requirements. In other words, these problems are just begging to be checked.

Redo with a quick approximation.

(2 1/4) X (1 3/4) had better come out close to 2 X 2 = 4.
For problems of length, area, and volume, you can approximate the original shape with something easier, perhaps a square or a cube.