MAth lesson 79

THE TOP 3’S : 

THE TOP 3’S 3. Marissa 2. Mickey 1. Wesley

WARM-UP’s : 

WARM-UP’s 1. 5 - 3? 2. Write the decimal number AND fraction to name each point marked by an arrow on the number line above Example: A: decimal= .9 fraction= 9/10 A B C D 0 1 2 3 4 5 6 9 8 7

Comparing Decimal numbers* Counting Decimal Places and Writing Equivalent Decimal Numbers : 

Comparing Decimal numbers* Counting Decimal Places and Writing Equivalent Decimal Numbers

Comparing Decimal Numbers : 

Comparing Decimal Numbers To compare decimal numbers, we need to pay close attention to place value. The decimal point separates the whole number part of a decimal number from the fraction part Example: 5.06 Whole Number Decimal Fraction part

Examples: : 

Examples: Compare: 12.3 1.23 Although the same digits appear in both numbers in the same order, the numbers are not equal. The number 12.3 is a little more than 12 but is less than 13. The number 1.23 is more than one but less than 2. so 12.3 is greater than 1.23 12.3 > 1.23

Slide 6: 

Example: Arrange these numbers in order from least to greatest: 1.02, 1.2, 1.12 The whole number part of each number is 1, so we need to compare the fraction part. The first digit to the right of the decimal points in the tenths’ place. The number 1.02 has a zero in the tenths’ place. The number 1.12 has a one in the tenths’ place, and the number 1.2 has a two in the tenths’ place. This is enough information to place the numbers in order: 1.02, 1.12, 1.2

LET’S PRACTICE: : 

LET’S PRACTICE: A. Compare 3.21 32.1 3.21 < 32.1 B. 44.4 4.44 44.4 > 4.44 C. Write these numbers in order from least to greatest: 2.4, 2.04, 2.21 2.04, 2.21, 2.4

Counting Decimal Places : 

Counting Decimal Places When talking about decimal numbers, we may use the term “decimal places.” By decimal places we mean the number of digits to the right of the decimal point. Example: The number 1.234 is written with three decimal places. The number 15.2 is written with one decimal place. Money is usually written with two decimal places: $100.00

Writing Equivalent decimal Numbers : 

Writing Equivalent decimal Numbers We may add decimal places to a number without changing the value of the number without changing the value of the number by attaching one or more zeros to the right of the last decimal place. Example: we can write 0.3 as 0.30 (it’s the same thing!) The zero does NOT change the number because it does not change the place value of the three. In both numbers 3 is in the tenths’ place. So, 0.3 = 0.30

More Examples: : 

More Examples: Write 12.6 with three decimal places The number 12.6 is written with one decimal place. By attaching two zeros, we can write it with three decimal places, 12.600 Compare: 12.6 12.600 We see that the whole-number parts of these two numbers are the same. The fractions part seems to be different, but both numbers have a 6 in the tenths’ place. If we add two zeros to 12.6 so that 12.6 has three decimal places, we see that the numbers are the same. 12.600 = 12.600

Let’s Practice: : 

Let’s Practice: Write each of these numbers with three decimal places: A. 1.2 B. 4.08 C. 0.50000 Answers: A. 1.200 B. 4.080 C. 0.500 Compare: A. 50 500 B. 0.4 0.04 C. 0.2 0.20000 Answers: A. 50 < 500 B. 0.4 > 0.04 C. 0.2 = 0.20000