Chapter 2: Applications of Decimals

Section 2-1 Comparing and Rounding Decimals Rounding Decimals is similar to rounding whole numbers.

Example 1: Round 1.73628 to the nearest hundredth. Step one: locate the hundredth place. Step two: look at the digit to the right of the hundredths place. Step three: Is that # 5 or larger if so round up, if not the number stays the same. Write the new number. 1.74

More examples: Round 13.422 to the nearest tenth Step 1: Locate the tenth place Step2: look at the digit to the right of the tenths place. Step three: Is that # 5 or larger if so round up, if not the number stays the same. Write the new number. 13._

Get your marker and marker board, or paper and pencil. Working with the person beside you make up two problems and do the problems together.

Any questions? Work on your rounding assignment for 5 minutes quietly on your own.

Comparing Decimals Selected Information from Baseball Cards of Three Players (Topps 1993) Name Deer Dunston Rookie At bats (AB) 393 73 26 Hits (H) 97 23 5 Doubles 20 3 1 Triples 1 1 0 Home runs 32 0 1 Slugging % .547 .384 .346 Batting Ave.247 .315 .192

How do we know which number is bigger 19.8,19.0, or 19.3? First compare the whole numbers (in this example the whole # is the same) Next compare the tenth place unit, and find which number is greater. The tenths are 8,0,3. Which is bigger? So _____ is the biggest.

Another example: Put these 3 #’s in order from least to greatest 7 Hint: Look at whole number first Then go to the tenth place Then examine the hundredth place Correct order:____________________

Make up 1 set of decimal numbers and have the person next to you put them in order from least to greatest.

How do we compare numbers? You can use a number line You can make a model You can use <, > symbols

Number Line Order 0.5,0.8, and 0.25 on a number line. _________________________________ 0 1

Number Line Order 0.5,0.8, and 0.25 on a number line. _________________________________ 0 0.25 0.5 0.8 1

Comparing using a model Draw a model of 0.58

Compare decimal numbers using <, > and = symbols < means less than > means greater than Compare 0.23 _____ 0.230 Compare 4.79 _____ 4.8 Compare 1.92 _____ 1.09

Practice Turn to the person next to you and compare numbers. You make up one number, your partner make up one number. Write them down comparing them using symbols.

Vocabulary word for this lesson   Equivalent decimals- numbers that name the same amount. Example: 0.4 and 0.40 are equivalent decimals. They name the same amount.

Review In this lesson you learned how to Round numbers Compare numbers to find least to greatest Compared numbers using…. Number line, models and symbols. Vocabulary word: Equivalent decimal

Assignment: Rounding worksheet Due Today And Page 52-53 Problems 1-33 Due Monday