Quick, what's 2' 9-11/16" + 17' 5-3/4"? If this problem leaves you reaching for a pencil and paper, the InchMate® Construction Calculator can save you a lot of time and headaches. With its dedicated imperial standard fraction keys, the Inchmate makes working with cumbersome feet-inch-fraction measurements what it should be—simple arithmetic. So how about dividing such dimensions or finding the rafter length for a roof with a 4' 2-1/2" rise and 12' 6-1/4" run? That, too, is solved in seconds by punching a few dedicated keys. Metric measurements are a cinch—the Inchmate can convert back and forth in an instant. Find the spacing for windows and doors, plan stair risers, calculate material costs, the list goes on; if you build things, the Sonin Inchmate is an indispensable tool.