About the Book YIKES!
Total Page:16
File Type:pdf, Size:1020Kb
Chapter 1 Fractions and Decimals Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. About the Book • Utilize and memorize the inside jacket (except Dimensional Analysis Method) • Read the MATH TIP boxes in each chapter • Know the RULE boxes in each chapter • Read the QUICK REVIEW box for every chapter • Practice the Review Sets from each chapter Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. YIKES! Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 1 How can You succeed in this class? LISTEN Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. FOLLOW DIRECTIONS Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. PRACTICE Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 2 Category of Fractions • Common Fractions, aka “fractions” example: ½ • Decimal Fractions, aka “decimals” example: 0.5 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Fractions numerator denominator • Math tip: – Denominator begins with “d” and is “down” • Below fraction line Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 4 Types of Fractions • Proper – Value of numerator is less than value of denominator (the result will always be less than 1 in this case) –Example: 5 is less than 1 8 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 3 Types of Fractions • Improper – Value of improper fraction (numerator is greater than denominator) is greater than 1 –Example: 8 is greater than 1 5 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Types of Fractions • When the numerator and denominator are the equal, the result is 1 •Examples: 4 11 1 and 1 4 11 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Types of Fractions • Mixed numbers – Whole number + proper fraction combined –Example: 5 1 is greater than 1 8 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 4 Types of Fractions • Complex – Numerator, denominator, or both contain fraction, decimal, or mixed number – Value may be: • Less than 1 • Greater than 1 • Equal to 1 5 Example: 5 1 5 2 10 5 8 1 8 2 8 1 8 4 2 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Equivalent Fractions • Express fraction in different form while maintaining value • Dosage calculation requires conversion of fractions to equivalent values by: – Reducing to lowest terms – Enlarging fraction – Converting to different type of fraction 2 2 2 1 1 1 3 3 Example: 4 4 2 2 3 3 3 9 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Reducing Fractions • Divide both terms by largest nonzero whole number that will divide evenly into both numerator and denominator • Value remains same • Example: 6 6 2 3 10 10 2 5 Note: If you don’t see the largest number right off, you may divide by smaller numbers until they are in lowest terms. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 5 Enlarging Fractions • Multiply both terms by same nonzero number • Value remains same • Example: 1 1 2 2 12 12 2 24 1 2 and Note: The fractions 12 24 are the same value, as are the two fractions on the previous slide, 63 and . 10 5 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Converting Mixed Numbers to Improper Fractions • Multiply whole number by denominator • Add product to numerator • Denominator and value remain same • Example: 5(28)516521 2 88 88 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Converting Improper Fractions to Mixed Numbers • Divide numerator by denominator • Remainder becomes numerator • If necessary, reduce to lowest terms • Example: 10 2 1 10 4 2 2 442 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 6 Comparing Fractions © Cengage Learning 2016 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Adding or Subtracting Fractions • Convert to equivalent fractions with least common denominators • Add or subtract numerators • Place value in numerator • Place least common denominator as denominator Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Adding or Subtracting Fractions • Convert answer to mixed number and/or reduce to lowest terms • Example: 3123126 1 1 444 4 4 2 Note: When adding and subtracting fractions, once you get the denominators the same, you only combine the numerators, not the denominators … leave the denominators alone. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 7 Multiplying and Dividing Fractions • To multiply: – Cancel terms in the numerators with terms in the denominators, multiply numerators, and multiply denominators • To divide: – Invert fraction after the divisor, change division sign to multiplication, cancel terms in numerator with terms in the denominator, and multiply • Convert results to mixed number and/or reduce to lowest terms Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Multiplying Fractions Example: 1 1 32 1 464 2 2 Example: 15 2 15 1 (rename to ) 30 5 30 2 12 1 (the 2's cancel) = 25 5 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Multiplying Fractions • To multiply mixed numerals, first convert them to improper fractions, and then multiply. Example: 11 34 23 71391 convert to improper fractions 23 6 1 convert to a mixed numeral = 15 6 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 8 Division of Fractions changed to 1 2 1 7 7 4 7 4 2 8 Dividend Divisor Inverted Quotient Divisor Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Decimals X X X X X . X X X X tens ones tenths hundreds thousands hundredths thousandths ten thousands ten ten thousandths ten Whole numbers Decimal point Decimal fractions Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Decimals • Words for all decimals end in “th(s)” – 0.001 read as one thousandth – 0.02 read as two hundredths – 0.7 read as seven tenths • 4.125 is read as four and one hundred twenty- five thousandths • A decimal is read as “and” • A decimal separates the whole and fractional part of the number Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 9 Reading Decimals 4 . 1 2 5 four and one-hundred twenty Ones Tenths Hundreds Thousandths five thousandths Rule: The decimal number is read by stating the whole number first, the decimal point as “and”, and then the decimal fraction by naming the value of the last decimal place. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Decimal Values: Decimal Point and Zeros • If decimal value less than one, add zero before decimal point – Does not change value – Example: .5 = 0.5 • Read as five tenths • You do not read the zero when it appears alone before the decimal. It is there to emphasize the decimal. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Decimal Values: Decimal Point and Zeros • Example: .5 – Avoid this writing of decimal fraction – Could be mistaken for whole number five • Example: 0.50 – Avoid trailing zero – Decimal may be missed • Example: 0.5 – Correct method of writing decimal fraction Note: In decimal number, zeros added after last digit do not change the value but should not be used in medication orders. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 10 Comparing Decimals • Compare 0.125, 0.05, and 0.2 to find largest decimal fraction • Align decimal points and add zeros so that the decimal numbers are the same length. This doesn’t change the values. • 0.125 • 0.050 • 0.200 Which decimal is bigger? Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Comparing Decimals 125 0.125 or one hundred twenty-five thousandths 1, 000 50 0.050 or fifty thousandths 1,000 200 0.200 or two hundred thousandths 1,000 • 0.2 is largest decimal • 0.05 is smallest decimal Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Converting between Fractions and Decimals • Converting fraction to decimal – Divide numerator by denominator • Example: Convert 1 to decimal 4 .25 1 4 1.00 0.25 4 8 20 20 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 11 Converting Between Fractions and Decimals • Converting decimal to fraction – Decimal number becomes numerator – Denominator is number one followed by as many zeros as number of decimal places to right of decimal point – Reduce to lowest terms Example: convert 0.125 to fraction Numerator = 125 Denominator = 1,000 Reduce 125 1 1, 000 8 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Adding and Subtracting Decimals • To add or subtract decimals: – Align decimal points and add zeros – If necessary, add zeros to make all decimals equal length – Eliminate any unnecessary zeros when you get your answer, to avoid confusion Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Adding and Subtracting Decimals •Examples: – Add 1.25 and 1.75 1.25 1.75 3.00 3 – Subtract 2.1 from 3.75 3.75 2.10 1.65 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 12 Multiplying and Dividing Decimals • To multiply decimals: – Multiply number – Place decimal point in product by moving decimal to left number of places equal to sum of decimal places in numbers multiplied – Eliminate any unnecessary zeros • Example: 0.25 0.2 0.050 0.05 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Multiplying and Dividing Decimals • To divide decimals: – Move decimal point in divisor and dividend correct number of decimal places to make divisor a whole number – Align it in quotient • Example: 20. 1.2 24.0. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Multiplying and Dividing Decimals • To multiply or divide by multiplier of 10: –To multiply, move decimal point to right –To divide, move decimal point to left – Move same number of decimal places as there are zeros in multiplier of 10 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. 13 Multiplying and Dividing Decimals •Examples: 5.06 10 5.0.6 50.6 2.1 100 .02.1 0.021 Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED. Rounding Decimals • Rounded to hundredths – Two places Hundredths Tenths Thousandths 0 .1 2 3 0.12 1. 7 4 4 1.74 5 . 3 2 5 5.33 0 . 6 6 6 0.67 Copyright © 2016 Cengage Learning.