<p>If you practice enough, you will understand the material like it’s second nature and be able to run through the problems without thinking twice. But there will always be a couple of more problems that you might go back and try again. It’s better to double check your work anyway. Also, you should always plug your solutions back in to the original equations to verify your answer. This way you know whether or not you did something wrong. You should probably practice more if all this is not coming to you.</p>