PhotoRead the book. Math is not just reading it's analytical thinking. You want to understand the formulas. When you don't they become difficult to work out correctly. So of you're having difficulty with the subject PhotoRead it more often. Daily for a couple of weeks.
Math requires proving you know the formula. My math teacher taught it's a waste of time doing every single self-test exercise they have in a text book. Start with one of the middle ones. If you do okay wit that do two or three more. Usually the last two or three. Do them without stalling go to the next set, you understand and know it. If not start from the top do more until you understand the formula. As a PhotoReader I recommend PhotoReading the text again, in particular that section, 2 chapters before and two after it (so the core chapter is sandwiched. Take a break and come back to it again after a 20 minute incubation.
Alex
