Amazon.com description: Product Description: Avoid the mathematical mistakes that can add up to thousands of dollars in lost profits with this straightforward, easy-to-use tool. DEWALT Construction Math Professional Reference offers step-by-step explanations of over 100 useful formulas and field calculations that will aid in performing the basic math calculations necessary for the everyday contractor. From performing a full-blown take off to calculating materials needed to finish items on a punch list, these are skills that contractors need to be effective in their jobs. With practical examples and a useful on-the-job format, this is an indispensable part of any contractorsÂ' jobsite toolbox or reference library.