Check to see if the IBEW or IEC Chapter in your area has any prep classes. You will learn the correct way to do the calculations without beating your brains up trying to figure out how the author arrived at his/her answer. I have found that in most all classes, 75% of the people studying for an exam are scared to death that they will fail because of the calculations. The formulas aren't hard - you just have top know what to use when. Then practice, practice, practice. If you take a computer version of the ICC test, the formulas are on a different tab in the test. (Just hit a button and all of the electrical formulas are there - you still have to know which one to use.) The class setting far exceeds the "DIY" in preparing a person for any exam. You will find that if you have a question, probably 10 other guys are scratching their head about the same thing. Funny, most adult learners are embarrassed to ask a question for fear of appearing ignorant. But that is where the real learning takes place. Enjoy yourself and know you are on the path to creating more wealth for you and your family