Rounding

Decimals

I like tolook on the brightside of things, so I ALWAYS round up!

Is that bad?

And Understanding Place Value

Place Value and RoundingTable of Contents

Part 1: Understanding Place ValuePart 2: Rounding Whole NumbersPart 3: Rounding Decimals

Place ValuePart 1:

UnderstandingPlace Value

Place ValueBefore we can learn to round, we need to know the placevalues of whole numbers and decimals.Place Value – the value of a digit depending on its place or position in a number.

Place Value5,247.183Whole numbers – numbers to the LEFT of the decimal point. They are 1 or greater.

Decimals – numbersto the RIGHT of the decimal point.They are less than 1.

(Sample number)

Place Value

5, 267, 418 . 391on

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Can you name all of the

place value positions below?

(Sample number)

Place Value

How to properly say and write decimals: 18.3 eighteen and three tenths7.45seven and forty-five hundredths 0.126zero and one hundred twenty-six thousandthsNotice how the word “and” replaces the decimal point.

Place Value Practice1. 7,342

3. 12, 5715. 4,218,5057. 63.049. 983,762

2. 45.9384. 627,1946. 0.6158. 8,520.110. 402.61

Name the place of each underlined digit.

tens hundredths

thousands hundred thousands

millions thousandths

ones hundreds

ten thousands tenths

State the value ofeach underlined digit.

Place Value Practice1. 52, 175

2. 4.693. 7,218,5054. 78.6135. 284,267

Say or write the following numbers.1. 14,0272. 0.7133. 9,2164. 5.95. 8,000,156

two thousand

six tenths

seven million

one hundredth

eighty thousand

fourteen thousand, twenty-seven

seven hundred thirteen thousandths

nine thousand, two hundred sixteen

five and nine tenths

eight million, one hundred fifty-six

Rounding

Part 2:Rounding

Whole Numbers

Let’s start by rounding whole numbers!Rounding Whole NumbersExample 1:

Round the following number to the nearest hundred.

Step 1: Underline the hundred’s place.Step 2: Look at the number to the right of the underlined digit.5,368

Step 3: If the number on the right is 5 or more, add one to the underlined number, and then turn the rest of the numbers on the right into zeros.

= 5,4005,368Example 1 continued:

Round the following number to the nearest hundred.

Step 3: If the number on the right is 4 or less, leave the underlined number alone, and turn all numbers on the right side of the underlined number into zeros.

Rounding Whole Numbers

or

Example 3:Round the following number to the nearest million.2,036,194Step 1: Underline the million’s place.Step 2: Look at the number to the right of the 2.Step 3: The two stays the same in this case.Step 4: All numbers to right of the underlined number turn into zeros.

= 2,000,000Rounding Whole Numbers

Example 4:Round the following number to the nearest ten.496Step 1: Underline.Step 2: Look to the right of 9.Step 3: Round the 9 up to 10 and carry the 1 over to the 4, making it a 5.Step 4: All numbers to right of the underlined number turn to zero.

= 50 0Rounding Whole Numbers

Let’s practice!

Rounding Whole number's PracticeRound the following numbers to each underlined place.1. 4,157

3. 6,014,8815. 7,971,0157. 125,652

2. 86,3034. 5626. $433.298. 71,407

4,200

6,000,000 560

8,000,000

126,000

90,000

$430.00

71,410

Rounding

Part 3:Rounding Decimals

Rounding DecimalsExample 1:

Round the following decimal to the nearest hundredth.1.252Step 1: Underline.Step 2: Look to the right of 5.Step 3: The 5 stays the same.

= 1.25Step 4: Cut off all numbers on the right of the underlined number.

Rounding DecimalsExample 2:

Round the following decimal to the nearest tenth.9.473Round the 4 to a 5, and remove all the numbers to the right of the underline.

= 9.5

Example 3:Round the following money amount to the nearest penny.

Rounding Decimals$3.9981Round the 9 to a 10.Carry the 1 to make the next 9 a 10.Carry that 1 to change the 3 into a 4.

= $4.00 Cut off the 8 and 1. Let’s practice!

Round the following decimals to each underlined place.1. 8.53. 3.7815. 9.8657. $7.4951

2. 0.6244. 1.73166. 0.9528. $862.99

9 0.62

3.8 1.732

9.87 1

$7.50 $860.00

Rounding Decimal’s Practice

Rounding Decimal’s PracticeRound the following numbers to the place indicated.1. thousandths; 0.06443. hundredths; 4.8885. thousandths; 2.75157. nearest penny; $55.386

2. tenths; 0.7984. tenths; 114.346. hundredths; 4.9968. nearest dime; $65.46

0.064

4.89

2.752

$55.39

0.8

114.3

5

$65.50