1. Rounding Decimals

2. Common Core Objective/Student Friendly Terms:
Rounding Decimals
Essential Question:
How do I round decimals?
Common Core Objective/Student Friendly Terms:
(6.NS.3) Students will be able to add and subtract two, three, or four decimals with like and unlike place values with at least 90% accuracy.

3. Rounding Decimals
Example: Ana buys her lunch from the cafeteria every day. She buys a slice of pizza for $1.35, a drink for $1.15, and some fruit for $.85. If she rounded to the nearest half dollar, about how much does she need to bring each day?
$1.35 ≈ $1.50
$1.15 ≈ $1.00
≈ $3.50
$0.85 ≈ $1.00

4. Rules for Rounding Decimals
Underline The Digit To Be Rounded
Look At The Digit To The Right Of Place Value Being Rounded
If the digit is 4 or less, the underlined digit remains the same
If the digit is 5 or more, add 1 to the underlined digit

5. Example #1: Round 5.214 to the nearest whole number.
Rounding Decimals
Example #1: Round to the nearest whole number.
Then look at the digit to the right
Underline the digit to be rounded 5
In this case the digit is the tenths place. Since 2 is less than 5 the digit ones remains the same
In this case the digit is the ones place
5.214 2
If we had looked on the number line we could also see that is closer to 5.0 than to 6.0.

6. Example #2: Round 76.385 to the nearest tenth.
Rounding Decimals
Example #2: Round to the nearest tenth.
Then look at the digit to the right
Underline the digit to be rounded
76.4
In this case the digit is the hundredths place. Since 8 is greater than 5, add 1 to the underlined #
In this case the digit is the tenths place
76.385 8
If we had looked on the number line we could also see that is closer to 76.4 than 76.3.

7. Rounding Decimals
Example #3: A bag of potato chips costs $ per ounce. How much does it cost?
Then look at the digit to the right
Underline the digit in the hundredths place
$0.53
In this case the digit is the thousandths place. Since 7 is greater than 5, add 1 to the underlined #
$0.5272 7

8. Rounding Decimals
Example: Mr. Williams wants to buy a Nintendo Wii. While looking on the internet, he noticed Wal-Mart had a special for $ He also noticed there was a special on games, $39.79 each, and he wants to buy three. Since it is the tax-free weekend no tax added to the sale. About how much money does he need to take with him?

9. Guided Practice: Rounding Decimals
Round each number to the decimal specified below: 1)
7.17; tenths 2)
; tens 3)
55.624; ones 4)
; hundredths

10. Guided Practice: Rounding Decimals Answers: 1) 7.2 2) 4080 3) 56 4)
948.31

11. Independent Practice:
Rounding Decimals
Independent Practice:
Round each number to the decimal specified below: 1)
25.57; tenths 2)
401.43; tens 3)
; ones 4)
; hundredths

12. Independent Practice:
Rounding Decimals
Independent Practice:
Answers: 1)
25.6 2)
400 3)
276 4)
111.32

13. Rules for Rounding Decimals
Underline The Digit To Be Rounded
Look At The Digit To The Right Of Place Value Being Rounded
If the digit is 4 or less, the underlined digit remains the same
If the digit is 5 or more, add 1 to the underlined digit

14. HOMEWORK Period 2: p.98 #13-36, all Period 3: p.98 #13-30, all
Rounding Decimals
HOMEWORK
Period 2: p.98 #13-36, all
Period 3: p.98 #13-30, all
Period 4: p.98 #13-21, all
Period 6: p.98 #13-21, all