Comparing and Ordering Comparing and Ordering DecimalsDecimals

When Will I Ever Do That???!!!When Will I Ever Do That???!!!

McMcDoDonanaldld’s M’s Menenu….u….I’m Lovin It!!I’m Lovin It!!

Double Cheeseburger: $ .99Double Cheeseburger: $ .99 Big Mac Value Meal: $ 4.79Big Mac Value Meal: $ 4.79 Chicken McNuggetts Meal: $ 3.80Chicken McNuggetts Meal: $ 3.80 Small Drink: $ .99Small Drink: $ .99 McFlurry: $ 1.97McFlurry: $ 1.97 Salad: $ 4.80Salad: $ 4.80 2 Cheeseburger Meal: $ 3.702 Cheeseburger Meal: $ 3.70 Ice Cream Cone: $ .87Ice Cream Cone: $ .87

Order Up!Order Up!Least Expensive to Most Least Expensive to Most

ExpensiveExpensive Ice Cream Cone .87Ice Cream Cone .87 Double Cheeseburger: .99Double Cheeseburger: .99 Small Soft Drink: .99Small Soft Drink: .99 McFlurry: 1.97McFlurry: 1.97 2 Cheeseburger Meal: 3.702 Cheeseburger Meal: 3.70 Chicken McNuggetts Meal: 3.80Chicken McNuggetts Meal: 3.80 Big Mac Value Meal: 4.79Big Mac Value Meal: 4.79 Chicken Salad: 4.80Chicken Salad: 4.80

What Do I Mean Compare What Do I Mean Compare Decimals?Decimals?

When we compare we use terms such as:When we compare we use terms such as: Less than <Less than < Greater than >Greater than > Equal to =Equal to =

Comparing decimals is similar to Comparing decimals is similar to comparing whole numbers.comparing whole numbers. 45<4745<47 150>105150>105

When we compare decimals we use place When we compare decimals we use place value or a number line.value or a number line.

Place ValuePlace Value

1,0001,000 101000

1010 11 0.10.1 0.010.01 0.000.0011

0.0000.00011

Compare Sara’s score Compare Sara’s score with Danny’s score.with Danny’s score.

1.1. Line Up Decimal PointsLine Up Decimal Points Sara: 42.1Sara: 42.1 Danny: 42.5Danny: 42.5

2.2. Start at the left and find the Start at the left and find the first place where the digits first place where the digits differ. Compare the digitsdiffer. Compare the digits

1<5 1<5 42.1<42.542.1<42.5 This means Sara’s score This means Sara’s score

was lower than Danny’s was lower than Danny’s score.score.

SaraSara 42.142.1

DannyDanny 42.542.5

RossRoss 42.042.0

BethanBethanyy

40.740.7

JacobJacob 46.146.1

Half pipe Results

Let’s Try Using A Number Let’s Try Using A Number LineLine

SaraSara 42.142.1

DannyDanny 42.542.5

RossRoss 42.042.0

BethanyBethany 40.740.7

JacobJacob 46.146.1

42.0 42.1 42.5

Numbers to the right are greater than numbers to the left. Since 42.5 is to the right of 42.1 we have:

42.5>42.1

Equivalent DecimalsEquivalent Decimals

Decimals that name the same Decimals that name the same number are called equivalent number are called equivalent decimals.decimals.

0.60 and 0.6 0.60 and 0.6

Are these the same???Are these the same???

0.60

0.6=

Annexing ZerosAnnexing Zeros

This means placing a zero to the This means placing a zero to the right of the last digit in a decimal.right of the last digit in a decimal.

0.6 0.600.6 0.60 Although we added a zero, the value Although we added a zero, the value

of the decimal did not change!!of the decimal did not change!! Annexing or adding zeros is useful Annexing or adding zeros is useful

when ordering a group of decimals.when ordering a group of decimals.

Ordering DecimalsOrdering Decimals

We can order decimals from least to We can order decimals from least to greatest or we can order from greatest or we can order from greatest to least.greatest to least.

Let’s try an example:Let’s try an example:

Order 15, 14.95, 15.8, and 15.01 Order 15, 14.95, 15.8, and 15.01 from least to greatestfrom least to greatest

First, line up the decimal pointsFirst, line up the decimal points

1515

14.9514.95

15.815.8

15.0115.01

15, 14.95, 15.8, 15.0115, 14.95, 15.8, 15.01

15, 14.95, 15.8, 15.0115, 14.95, 15.8, 15.01

Next, annex zeros so that each Next, annex zeros so that each number has the same number of number has the same number of decimal placesdecimal places

15.0015.00

14.9514.95

15.8015.80

15.0115.01

15, 14.95, 15.8, 15.0115, 14.95, 15.8, 15.01

Finally, use place value to compare the Finally, use place value to compare the decimals. Always start from the left!!decimals. Always start from the left!!

15.0015.00

14.9514.95

15.8015.80

15.0115.01 14.95, 15, 15.01, 15.814.95, 15, 15.01, 15.8

One More ExampleOne More Example

Order these numbers from greatest Order these numbers from greatest to leastto least

35.06, 35.7, 35.5, 35.84935.06, 35.7, 35.5, 35.849