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Chapter 6 Decimal Review (plus more). Slideshow Outline. Introduction to Decimals Order and Rounding Adding and Subtracting Decimals Multiplying Decimals and Circumference of a Circle Dividing Decimals and Order of Operations Fractions and Decimals. Introduction to (review of) Decimals.
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Slideshow Outline • Introduction to Decimals • Order and Rounding • Adding and Subtracting Decimals • Multiplying Decimals and Circumference of a Circle • Dividing Decimals and Order of Operations • Fractions and Decimals
Section Objectives • Decimal Notation and Writing Decimals in Words • Writing Decimals in Standard Form • Writing Decimals as Fractions • Writing Fractions as Decimals
Decimal Notation and Writing Decimals in Words Decimal part Whole number part Decimal point
Decimal Notation and Writing Decimals in Words 65 = . 65 100 EXAMPLE Write 47.65 in words. SOLUTION 4 7 . 6 5 hundredths. Forty-seven and sixty-five
Writing Decimals in Standard Form EXAMPLE Write twelve and six hundredths in standard form.. SOLUTION twelve and six hundredths 1 2 0 6 .
Writing Fractions as Decimals EXAMPLE Write as a decimal. (Hint: When the denominator is a power of 10, we can write it by reversing the procedure used in Slide 7.) SOLUTION
Section Objectives • Comparing Decimals • Rounding Decimals
Comparing Decimals To compare decimals, compare digits in the same place values from left to right. EXAMPLE
Rounding Decimals EXAMPLE Round 0.5942 to the nearest thousandth. SOLUTION Step 1: Locate the digit to the right of the given place value. 0.5942 2 is to the right of the thousandth place value. Step 2: If this digit is 5 or greater, add 1 to the digit in the given place value and delete all digits to its right. If this digit is less than 5, delete all digits to the right of the given place value. Since 2 is less than 5, we delete all digits to the right of the thousandths place value. 0.5942 0.594
Section Objectives • Adding Decimals • Subtracting Decimals • Estimating While Adding or Subtracting Decimals • Solving problems by Adding or Subtracting Decimals
Subtracting Decimals EXAMPLE Subtract 3.3 from 28. SOLUTION
Estimating When Adding or Subtracting Decimals EXAMPLE Subtract 2.1 from 7.6. SOLUTION Exact Estimate Since 5.5 is close to 6, our answer is reasonable.
Solving Problems by Adding or Subtracting Decimals EXAMPLE A pair of eyeglasses costs a total of $347.89. The frames of the glasses are $97.23. How much do the lenses of the eyeglasses cost? SOLUTION The lenses of the eyeglasses cost $250.66.
Multiplying Decimals and Circumference of a Circle
Section Objectives • Multiplying Decimals • Estimating When Multiplying Decimals • Multiplying by Powers of 10 • Finding the Circumference of a Circle • Solving Problems by Multiplying Decimals
Multiplying Decimals Total of 2 decimal places. Decimal placed at two decimal places.
Estimating When Multiplying Decimals EXAMPLE Multiply: SOLUTION Exact Estimate Since 22.26 is close to our estimate of 20, it is a reasonable answer.
Finding the Circumference of a Circle radius diameter or
Finding the Circumference of a Circle EXAMPLE Find the circumference of the following circle. 9.1 yards SOLUTION
Solving Problems by Multiplying Decimals EXAMPLE Jose Severos, an electrician for Central Power and Light, worked 40 hours last week. Calculate his pay before taxes for last week if his hourly wage is $13.88. SOLUTION Jose Severos’ pay before taxes for last week is $555.20.
Section Objectives • Dividing Decimals • Estimating When Dividing Decimals • Dividing Decimals by Powers of 10 • Solving Problems by Dividing Decimals • Simplifying Expressions with Decimals
Estimating When Dividing Decimals EXAMPLE Divide: SOLUTION Exact Estimate Since 0.045 is close to our estimate of 0.05, the answer is reasonable.
Solving Problems by Dividing Decimals EXAMPLE Dorren Schmidt pays $73.86 per month to pay back a loan of $1772.64. In how many months will the loan be paid off? SOLUTION Dorrin Schmidt will have his loan paid off in 24 months.
Simplifying Expressions with Decimals EXAMPLE Simplify 1.4(2-1.8). SOLUTION
Section Objectives • Writing Fractions as Decimals • Comparing Decimals and Fractions • Solving Area Problems Containing Fractions and Decimals
Writing Fractions as Decimals EXAMPLE Write as a decimal. SOLUTION Elayn Martin-Gay, PEARSON PRENTICE HALL, BASIC COLLEGE MATHEMATICS, 3e – Slide #38
Solving Area Problems Containing Fractions and Decimals EXAMPLE The area of a triangle is Find the area of the following triangle. 4.4 feet 17 feet SOLUTION Write as .5.