Idiot's Guides: Basic Math And Pre-algebra

No one likes a know-it-all. Most of us realize there’s no such thing— how could there be? The world is far too complicated for someone to understand everything there is to know. So when you come across a know-it-all, you smile to yourself as they ramble on because you know better. You understand that the quest for knowledge is a never-ending one, and you’re okay with that. You have no desire to know everything, just the next thing. You know what you don’t know, you’re confident enough to admit it, and you’re motivated to do something about it. At Idiot’s Guides, we, too, know what we don’t know, and we make it our business to find out. We find really smart people who are experts in their fields and then we roll up our sleeves and get to work, asking lots of questions and thinking long and hard about how best to pass along their knowledge to you in the easiest, most-accessible way possible. After all, that’s our promise—to make whatever you want to learn “As Easy as It Gets.” That means giving you a well-organized design that seamlessly and effortlessly guides you from page to page, topic to topic. It means controlling the pace you’re asked to absorb new information— not too much at once but just what you need to know right now. It means giving you a clear progression from easy to more difficult. It means giving you more instructional steps wherever necessary to really explain the details. And it means giving you fewer words and more illustrations wherever it’s better to show rather than tell. So here you are, at the start of something new. The next chapter in your quest. It can be an intimidating place to be, but you’ve been here before and so have we. Clear your mind and turn the page. By the end of this book, you won’t be a know-it-all, but your world will be a little less complicated than it was before. And we’ll be sure your journey is as easy as it gets. Mike Sanders Publisher, Idiot’s Guides Basic Math and Pre-Algebra by Carolyn Wheater A member of Penguin Group (USA) Inc. ALPHA BOOKS IDIOT’S GUIDES and Design are trademarks of Penguin Group (USA) Inc. Published by Penguin Group (USA) Inc. Penguin Group (USA) Inc., 375 Hudson Street, New York, New York 10014, USA • Penguin Group (Canada), 90 Eglinton Avenue East, Suite 700, Toronto, Ontario M4P 2Y3, Canada (a division of Pearson Penguin Canada Inc.) • Penguin Books Ltd., 80 Strand, London WC2R 0RL, England • Penguin Ireland, 25 St. Stephen’s Green, Dublin 2, Ireland (a division of Penguin Books Ltd.) • Penguin Group (Australia), 250 Camberwell Road, Camberwell, Victoria 3124, Australia (a division of Pearson Australia Group Pty. Ltd.) • Penguin Books India Pvt. Ltd., 11 Community Centre, Panchsheel Park, New Delhi—110 017, India • Penguin Group (NZ), 67 Apollo Drive, Rosedale, North Shore, Auckland 1311, New Zealand (a division of Pearson New Zealand Ltd.) • Penguin Books (South Africa) (Pty.) Ltd., 24 Sturdee Avenue, Rosebank, Johannesburg 2196, South Africa • Penguin Books Ltd., Registered Offices: 80 Strand, London WC2R 0RL, England Copyright © 2014 by Penguin Group (USA) Inc. All rights reserved. No part of this book may be reproduced, scanned, or distributed in any printed or