Math For Real Life For Dummies E-Book

Barry Schoenborn

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 353

Veröffentlichungsjahr: 2013

Beschreibung

The easy way to brush up on the math skills you need in real life Not everyone retains the math they learned in school. Like any skill, your ability to speak "math" can deteriorate if left unused. From adding and subtracting money in a bank account to figuring out the number of shingles to put on a roof, math in all of its forms factors into daily life. Math For Real Life For Dummies provides you with the simple formulas and theorems that you're likely to encounter in the workplace, the kitchen, and even when playing games. You can turn to Math For Real Life For Dummies to brush up on your math skills or to handle everyday encounters, like calculating restaurant tips, understanding interest rates, and figuring out percentages and odds. Packed with real-world examples that make sense, Math For Real Life For Dummies takes the stress out of your daily calculation encounters. * Provides tips for understanding and using basic mathematical concepts * Shows you how math helps the mind to reason and organize complicated situations or problems into clear, simple, and logical steps * Covers all of the math skills you're likely to need in everyday situations If you're looking for a practical, plain-English guide to mastering everyday math skills, Math For Real Life For Dummies has you covered.

Leseprobe

Math For Real Life For Dummies®

Published byJohn Wiley & Sons, Inc.111 River St.Hoboken, NJ 07030-5774www.wiley.com

Copyright © 2013 by John Wiley & Sons, Inc., Hoboken, New Jersey

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Control Number: 2012955837

ISBN 978-1-118-45330-8 (pbk); ISBN 978-1-118-45332-2 (ebk); ISBN 978-1-118-45334-6 (ebk); ISBN 978-1-118-45331-5 (ebk)

Manufactured in the United States of America

10 9 8 7 6 5 4 3 2 1

About the Author

Barry Schoenborn lives in Nevada City, California. He’s a longtime math, science, and technical writer, with over 35 years’ experience. He’s written hundreds of user manuals. In the past, Barry’s tech-nical writing company worked with the State of California agency CalRecycle to teach scientists and administrators how to write clearly.

Barry’s the coauthor of Technical Math For Dummies, Medical Dosage Calculations For Dummies, Physician Assistant Exam For Dummies, and Storage Area Networks: Designing and Implementing a Mass Storage System.

He was a movie reviewer for the Los Angeles Herald-Dispatch newspaper and wrote a monthly political newspaper column for The Union newspaper of Grass Valley, California, for seven years. He also writes “dental humor,” a funny genre that nobody except a dentist would want to read.

Barry’s publishing company, Willow Valley Press, published Dandelion Through the Crack, which won the William Saroyan International Prize for Writing.

Dedication

I dedicate this book to Lynda Straus, my long-time intimate friend. She is one of the brightest people I know and is an excellent technical writer. However, she stays very busy, mostly acting as caregiver for her mother and has never made math a focus. Oops! In many ways, she is my model for the ideal reader of this book.

Author’s Acknowledgments

I want to thank Lindsay Lefevere, Executive Editor, for the opportunity to write this book. A big thanks, too, to Matt Wagner of Fresh Books Literary Agency, who presented me to Wiley.

Many thanks to the Wiley team: Tracy Barr, Project Editor, and Michael McAsey and Shira Fass, the technical reviewers. They worked very hard to make this book more accurate and easier to read. Without them, there wouldn’t be a book.

Publisher’s Acknowledgments

We’re proud of this book; please send us your comments at http://dummies.custhelp.com. For other comments, please contact our Customer Care Department within the U.S. at 877-762-2974, outside the U.S. at 317-572-3993, or fax [phone].

Some of the people who helped bring this book to market include the following:

Acquisitions, Editorial, and Vertical Websites

Editor: Tracy L. Barr

Executive Editor: Lindsay Sandman Lefevere

Assistant Editor: David Lutton

Editorial Program Coordinator: Joe Niesen

Technical Editors: Michael McAsey, Shira Fass

Senior Editorial Manager: Jennifer Ehrlich

Editorial Manager: Carmen Krikorian

Editorial Assistant: Alexa Koschier

Cover Photos: © PixelEmbargo / iStockphoto.com

Cartoons: Rich Tennant (www.the5thwave.com)

Composition Services

Project Coordinator: Patrick Redmond

Layout and Graphics: Carrie A. Cesavice, Joyce Haughey, Melissa Smith, Christin Swinford

Proofreader: Wordsmith Editorial

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Publishing and Editorial for Consumer Dummies

Kathleen Nebenhaus, Vice President and Executive Publisher

David Palmer, Associate Publisher

Kristin Ferguson-Wagstaffe, Product Development Director

Publishing for Technology Dummies

Andy Cummings, Vice President and Publisher

Composition Services

Debbie Stailey, Director of Composition Services

Math For Real Life For Dummies®

Visit www.dummies.com/cheatsheet/mathforreallife to view this book's cheat sheet.

Table of Contents

Introduction

About This Book

Conventions Used in This Book

What You’re Not to Read

Foolish Assumptions

How This Book Is Organized

Part I: Boning Up on Math Basics

Part II: Math for Everyday Activities

Part III: Math to Manage Your Personal Finances

Part IV: The Part of Tens

Icons Used in This Book

Where to Go from Here

Part I: Boning Up on Math Basics

Chapter 1: Awesome Operations: Math Fundamentals

Numbers You Can Count On

Reviewing the Four Basic Operations

Addition

Subtraction

Multiplication

Division

Finagling Fractions

Getting familiar with types of fractions

Reducing fractions

Adding, subtracting, multiplying, and dividing fractions

Converting fractions

Processing Percentages

Converting a common fraction to a percentage

Converting a percentage to a fraction

Grasping Charts and Graphs

Looking at line charts

Gobbling up pie charts

Bellying up to bar charts

Working Wicked Word Problems

Doing the analysis

Applying the math

Other story problem tricks

Chapter 2: High School Reunion: Revisiting Key Principles of Algebra and Geometry

“A” Stands for “Algebra” and “Awesome”

Getting acquainted with variables and constants

Expressions and equations

Operating with variables

Applying the same operation on both sides of the equal sign

Keeping order with operations

Jousting with Geometry: Simple Rules about Shape and Size

Looking at geometry’s basic parts: Planes, points, and lines

What’s your angle? Acute, obtuse, right angles, and more

The shape of things

Calculating areas

Getting pushed to the edge: Perimeters

Speaking volumes about boxes

Summing up geometry

Chapter 3: Becoming a Believer: Conversion, Statistics, Probability, and More

Wrangling Ratio-Proportion: The Best Calculation Method

Doing Conversions: Lots of Pleasure and Hardly Any Pain

Factoring in the conversion factor

Using United States customary units

Managing the metric system

Mastering Simple Statistics

An average is a mean thing

Mediating the median

Figuring percentiles

Being aware of statistical fallacies

Predicting the Probable

Determining probability

What are the odds?

Chapter 4: The Miracle of Mental Math

Mental Math Basics

Adding and Subtracting on the Fly

Adding numbers quickly

Subtracting numbers quickly

Making Hay of Multiplication and Division

Multiplying in your head

Dividing in your head

Estimating with Ease

Estimating sales tax and value added tax (VAT)

Estimating tips

Estimating guests at a banquet

Doing Simple Cerebral Statistics

Figuring averages

Managing medians

Part II: Math for Everyday Activities

Chapter 5: Let’s Make a Deal! Math You Use When Shopping

Determining Actual Cost

Finding the total cost of acquisition

Figuring the total cost of ownership

Uncovering hidden costs

Making Tradeoffs: A Fun Balancing Act

Buying in Quantity: A Good Deal?

Knowing the Real Cost of Sale Items

Counting coupons

Calculating percentage decreases: You save 10 percent!

Calculating the real percentages in “get one free” offers

Dealing with dining specials

Doubling down on discounts

How Do You Wanna Pay for That?

Capturing bargains with credit cards

Taking advantage of layaway

Discovering Deals at the Grocery

Estimating the whole grocery bill

Estimating how much to buy

Comparing unit prices

Comparing products per roll or square foot

Calculating volume (25 percent more free!)

Determining Where to Shop

Narrowing your choices

Looking at externalities

Gauging the impacts of different store types

Chapter 6: Mmm, Mmm, Good: Kitchen Calculations

Taking Measure

Knowing your units

Equivalencies — All things being equal

Scaling a Recipe

The keys to scaling a recipe

Scaling in action

Using Math to Buy and Cook Smart

Calculating per-serving costs

Taste by the ton: Buying in bulk

Chapter 7: It Does a Body Good: Math for Health and Well-Being

Figuring Your Nutritional Needs

Read the label, Mabel: Nutrition facts

Figuring out your ideal daily calorie intake

Following the recommended daily allowance

Calculating Calories

Counting calories in your food

Managing your weight with math

Comparing your current weight to your goal weight

Calculating BMI

Exercise Math

These METs won’t win a pennant: Metabolic equivalent of task

Figuring an activity’s calorie burn rate

Being the Doctor at Home

Understanding medicine labels

For good measure: Dispensing liquid medications

Chapter 8: Putting Geometry to Work at Home

Calculating Your Way to a Better Lawn and Garden

Figuring how much seed you need

Mulching math

Planting the seeds of success — mathematically

Knowing how much you really mow

Fixing Up the Place

Laying carpet

Calculating paint amounts

Pouring a patio

Chapter 9: Math and Statistics around Town and on the Road

Automobile Arithmetic: Figuring Costs, Mileage, and More

It’s a gas! Comparing fuel prices and mileage

Are we there yet? Figuring distance, time, and speed

Making sense of the mechanic’s bill

Dining Out

Calculating the tip

Splitting hairs and bills

Taking a Vacation: To Drive or to Fly?

Leaving on a jet plane

Driving: The daring alternative

Gambling: Money You Take to Las Vegas Stays in Las Vegas

Understanding odds, bets, and payouts

Playing the most popular games

The worst casino bets

Part III: Math to Manage Your Personal Finances

Chapter 10: Budgets, Bank Accounts, Credit Cards, and More

Beginning with a Budget

Identifying what’s in a budget

Using your math skills to make a budget

Applying budgeting principles

Balancing Your Checkbook

Homing in on Mortgage Math

Having a PITI party

Amortization: Paying down the loan

A second mortgage or home equity line of credit

Using Smart Math for Other Big Purchases

Cruising around car loan math

Studying up on education loans

Calculating How to Avoid or Get Out of a Credit Card Hole

Understanding how credit cards work

Avoiding annual and other fees

Paying down credit cards

Selecting Savings Accounts

Chapter 11: Key Principles of Investment Math

Factoring Personal Info into Investment Decisions

Knowing your tolerance for risk

Looking at your investment horizon

Choosing between appreciation or income

Playing with Instruments: Not the Musical Kind

Basic financial instruments

Climbing the investment pyramid

Growing the Green Stuff: The Time Value of Money

Calculating simple interest

Calculating compound interest

Calculating future value

Oh, see how it grows! The joys of making regular deposits

Rounding Up Retirement Plans

The feisty 401(k)/403(b): Defined contribution plans

Adding up IRAs and their kin

Making sensing of Social Security

Calculating current and future tax advantages

Managing Mutual Funds

Paying attention to fees

Figuring the average annual return

Considering Common Stocks

Processing P/E ratios

Figuring your dividends

Investing in Bonds

Calculating interest on bonds

Calculating yield

Chapter 12: Covering Your Assets: Insurance Math

Honing in on How Insurance Works

Spreading risk around

Evaluating risks

Determining premiums

Making Calculations about Your Own Lines of Insurance

Auto insurance

Homeowner’s insurance

Health insurance

Life insurance

Chapter 13: Taking Math to Work

Setting Prices

Managing markups

Figuring discounts

Predicting time and materials costs

Paying Attention to Profit

Calculating profit margin

Determining gross profit

Pre-tax profit

Net profit

Making Change

Tracking Your Time

The timesheet

Heavens, no — Not project accounting!

Parsing Your Paycheck

Calculating your gross pay

Figuring your net pay: All about deductions

Using Form W-4 to change how much is withheld

Chapter 14: How Taxing! (Almost) Understanding the Government

Illuminating Income Taxes

Taming Form 1040

Deciding whether to itemize

Observing Other Taxes

Surveying sales tax

Processing property tax

Fee, fie, foe, fum

Part IV: The Part of Tens

Chapter 15: Ten Quick Calculations You Can Do in Your Head

Miles to Kilometers

Miles to Your Destination

Time to Destination

Sales Tax and VAT

Tips

How Much Paint to Buy

Number of Pizzas to Buy

Blood Alcohol Content (BAC)

Dollars to Pounds or Euros

Gas Mileage

Chapter 16: Ten Activities That Build Math Skills

Playing Sudoku

Playing Elementary Math Games on the Internet

Working through Logic Puzzles

Noting the Birthday Paradox

Knowing the Value of Pi

Guessing a Friend’s Age

Playing Hidden Object Games

Flipping Coins

Playing Games with Your Kids

Playing Angry Birds

Cheat Sheet

Introduction

Math is great. I’ve spent my life enjoying math and getting the benefits from it. But many people don’t think math is so hot: They have fear and loathing.

The trouble is, a lot of what you learned in school probably was boring or painful, and most likely you forgot it right away. Or you may have deliberately not learned some types of math at all just to save yourself the trouble of forgetting them later. Why? Mainly because a lot of the math taught in schools wasn’t math you could use. Well, that nonsense stops here, because this book is filled with math you use. Here’s just a brief sampling of the areas where you’ll find real-life math to be useful: