Bài giảng môn học Quản trị kinh doanh - Chapter three: Decimals

Chapter ThreeDecimalsCopyright © 2014 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill/IrwinLU 3-1: Rounding Decimals; Fraction & Decimal ConversionsExplain the place values of whole numbers and decimals; round decimals.Convert decimal fractions to decimals, proper fractions to decimals, mixed numbers to decimals, and pure and mixed decimals to decimal fractions.Learning unit objectivesLU 3-2: Adding, Subtracting, Multiplying, and Dividing DecimalsAdd, subtract, multiply, and divide decimals.Complete decimal applications in foreign currency.Multiply and divide decimals by shortcut methods.Table 3.1 - Bag of M&M’s Decimal PercentColor Fraction (hundredth) (hundredth)Yellow 18 .33 32.73% 55Red 10 .18 18.18% 55Blue 9 .16 16.36% 55Orange 7 .13 12.73% 55Brown 6 .11 10.91% 55Green 5 .09 9.09% 55 Total 55 1.00 100.00% 55 = 1Decimal place-value chartRounding Decimals .337272 .33 .3272727Step 1. Identify the place value of the digit you want to round.Step 2. Identify the digit to the right. If 5 or more, increase the identified digit by 1. If less than 5, do not change. Step 3. Drop all digits to the right of the identified digit.3 StepsRounding DecimalsRound to nearest dollar: $166.39 Round to nearest cent: $1,196.885 Round to nearest hundredth: $38.563 Round to nearest thousandth: $1,432.9981 $1,432.998 $38.56$1,196.89 $166Converting Decimal Fractions to Decimals2 Steps1. Count the number of zeros in the denominator.2. Place the numerator of the decimal fraction to the right of the decimal point the same number of places as you have zeros in the denominator. Do not go over the total number of denominator zeros.Fraction Decimal # of places 3 10 3 100 3 1,000 3 10,000.31.032.0033.00034Converting Proper Fractions to Decimals344 3.00 2 8 20 20 0.75DecimalConverting Mixed Numbers to Decimals + .4 = 8.4 255 2.0 2 0 0 8 .4 Step 1Step 2 824 1 24 24 1002.24Step 1. Place the digits to the right of the decimal point in the numerator of the fraction. Omit the decimal point.Step 2. Put a 1 in the denominator of the fraction.Step 3. Add the same numberof zeros (as the places) to the denominator of the fraction. For mixed decimals, add the fraction to the whole number. Places: The number of digits to the right of the decimal point.Converting Pure Decimals to Decimal FractionsConverting Mixed Decimals to Decimal Fractions45 14517.45Step 1Step 3Places 451002 17.45Step 1. Place the digits to the right of the decimal point in the numerator of the fraction. Omit the decimal point.Step 2. Put a 1 in the denominator of the fraction.Step 3. Add the same number of zeros (as the places) to the denominator of the fraction. For mixed decimals, add the fraction to the whole number. Places: The number of digits to the right of the decimal point. 45 100 17Adding DecimalsAdd: 4 + 7.3 + 36.139 + .0007 + 8.22 4.0000 7.3000 36.1390 .0007 8.220055.6597 CHECK 4.0000 7.3000 36.1390 .0007 8.220055.6597Subtracting DecimalsSubtract: 45.3 - 15.273 45.300- 15.27330.027 CHECK 45.300- 15.273 = 30.027Multiplying Decimals 2.36x .016 1416 236 0377657.084(3 decimal places).03776(5 decimal places) 8.52 (2 decimal places) x 6.7 (1 decimal places)= 5964 5112 57084Need to add zeroDividing Decimals25. 328.00 25. 328.00 25 78 75 30 25 50 5013.12Step 1. Make the divisor a whole number by moving the decimal point to the right.2.5 32.800ExampleStep 2. Move the decimal point in the dividend to the right the same number of places as in the divisor (step 1). If there are not enough places, add zeros to the right of the dividend.Step 3. Place the decimal point in the quotient above the new decimal point in the dividend. Divide as usual.3 StepsDecimals Applications in Foreign CurrencyCHECK $612.60 x $1.0210 = $600.00Table factor from currency tableThe price of an Apple iPad 2 can be bought in Canada for $600 U.S. dollars. Using the currencies table from the Wall Street Journal let us see what the iPad 2 would sell for in Canadian dollars. In the table on page 74, 1 U.S. Dollar equals $1.0210 Canadian dollars . To find the cost in Canadian dollars:1. You multiply the number of U.S. dollars ($600) times $1.0210.$600 x $1.0210 = $612.602. To check your calculations, take the $612.60 Canadian dollars cost of the iPad 2 and multiply it by $0.9794. This is what the Canadian dollar is worth against the U.S. dollar. It equals $599.98 (this amount is off .02 due to rounding).Shortcuts for Multiples of 10Multiplication 6.89 x 106.89 x 1006.89 x 100068.96890Step 1. Count the zeros in the multiplier.Step 2. Move the decimal point in the multiplicand the same number of places to the right as you have zeros in the multiplier.689Shortcuts for Multiples of 10Division 6.89 / 106.89 / 1006.89 / 1000.689.00689.0689Step 1. Count the zeros in the divisor.Step 2. Move the decimal point the same number of spaces to the left.