rounding numbers to the nearest ten, hundred, and thousand

Rounding Numbers to the Nearest

Ten, Hundred, and Thousand

• Instructional Objective:– To Investigate and develop an understanding

of the base ten place value system

Click here to continue

What is rounding numbers?

You can estimate when you need to know about how many or about how much.

Rounding is one way to estimate.


Rounding to the Nearest Ten

You estimate which ten the number you are rounding is closest to. If you saw a road sign that said Flint was 17 miles away, then you

could say that Flint is about 20 miles away.

10 11 12 13 14 15 16 17 18 19 20

17 rounds to 20Because 17 is closer to 20 than 10

Flint 17 miles

continue

Look at these examples. Try to determine what the rule is for rounding to the nearest ten.

Choose the rule:If the number in the ones column

is 0, 1, 2, 3, or 4 then round up to the greater ten.

If the number in the ones column is 0,1,2,3, or 4, then round down to the lesser ten.

A

B

What does 12 round to?What does 93 round to?What does 15 round to?What does 77 round to?What does 22 round to?

Yes!! You are correct. When a number has a 0, 1, 2, 3, or 4 in the

ones column you round to the lesser ten! For example 83 rounds to 80.


Think of rounding like a car going over a hill. If you are to round 54 to the nearest ten, then your choices are either round back to 50 or up to 60. You always need to look at the number in the ones column. If the

car goes up to 54 and stops, then it will roll back to 50.

50

51

52

53

54

60

59

58

57

56

55

54 rounds to 50


Here is another example. If you are to round 87 to the nearest ten, then your choices are either round back to 80 or up to 90. If the car

goes to 87 and stops, then it will roll to 90.

80

81

82

83

84

90

89

88

87

86

85

87 rounds to 90


Now it’s your turn to round to the nearest ten!

Round 32

35

30

40

A

C

B

Sorry.

Remember the rules:

1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then

round down .

2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then

round up.

Click here to try again

Yes!! You are correct.



Round 67

70

100

60

A

B

C

Sorry.

Remember the rules:


round down .


round up.



Round 25

20

50

30

A

B

C

Sorry.

Remember the rules:


round down .


round up.


Next you will learn about rounding to the nearest hundred.

When rounding to the nearest hundred, you are finding out which hundred a number is

closest to.


Rounding to the Nearest Hundred

You estimate which hundred the number you are rounding is closest to. If you saw a road sign that said Swartz Creek was 230 miles away, then you

could say that Swartz Creek is about 200 miles away.

200 210 220 230 240 250 260 270 280 290 300

Swartz Creek230 miles

continue

230 is closer to 200

230 rounds to 200

Look at these examples. Try to determine what the rule is for

rounding to the nearest hundred.

241 rounds to 200

532 rounds to 500

Choose the rule:If the number in the tens column

is 0, 1, 2, 3, or 4 then round up to the greater hundred.

If the number in the tens column is 0,1,2,3, or 4, then round down to the lesser hundred.

A

B

Sorry.Look at the numbers in the tens column. Do they cause the number to be rounded to the

lesser hundred or the greater hundred?

Click here to try again.

Yes!! You are correct. When a number has a 0, 1, 2, 3, or 4 in the tens column you round

to the lesser hundred! For example 429 rounds to 400.



rounding to the nearest hundred.

381 rounds to 400

262 rounds to 300

958 rounds to 1000

Choose the rule:If the number in the tens

column is 5, 6, 7, 8, or 9 then round up to the greater hundred.

If the number in the tens column is 5, 6, 7, 8, or 9 then round down to the lesser hundred.

A

B

Sorry.Look at the numbers in the tens column. Do they cause the number to be rounded to the

lesser hundred or the greater hundred?


• Yes!! You are correct. When a number has a 5, 6, 7, 8, or 9 in the tens column you round to

the greater hundred!


Remember the example of the car going over the hill.When rounding to the nearest hundred, any number that ends in 49 or

less will cause the car to roll back to the lesser hundred and any number that ends in 50 or greater, will cause the car to roll up to the

greater hundred.If you round 720 to the nearest ten, then your choices are either round back to 700 or up to 800. If the car goes up to 720 and stops, then it

will roll back to 700.

700

710

720

730

740

800

790

780

770

760

750720 rounds to 700


Here is another example. If you round 360 to the nearest hundred, then your choices are either round back to 300 or up to 400. If the car

goes to 360 and stops, then it will roll to 400.

300

310

320

330

340

400

390

380

370

360

350

360 rounds to 400 Click here to continue

Now it’s your turn to round to the nearest hundred!

Round 236

200

300

400

A

C

B

Sorry.

Remember the rules:


round down .


round up.


Round to the nearest hundred.

Round 581

500

550

600

A

B

C

Sorry.

Remember the rules:


round down .


round up.


Round to the nearest hundred.

Round 749

600

700

800

A

B

C

Sorry.

Remember the rules:


round down .


round up.


Last you will learn to round to the nearest thousand!

When you round to the nearest thousand you are estimating which thousand the

number is closest to.


Rounding to the Nearest Thousand

You estimate which thousand the number you are rounding is closest to. If you saw a road sign that said Posen was 2600 miles away, then you could say that

Posen is about 3000 miles away. 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000

Posen 2600 miles

continue

2600 rounds to 3000

2600 is closer to 3000 than 2000


rounding to the nearest thousand.2456 rounds to 20005302 rounds to 50003289 rounds to 30007367 rounds to 70008422 rounds to 80007056 rounds to 70001245 rounds to 10009135 rounds to 9000

Choose the rule:If the number in the hundreds

column is 0, 1, 2, 3, or 4 then round up to the greater thousand.

If the number in the hundreds column is 0,1,2,3, or 4, then round down to the lesser thousand.

A

B

Sorry.Look at the numbers in the hundreds column. Do they cause the number to be rounded to

the lesser thousand or the greater thousand?

Click here to try again.

Yes!! You are correct. When a number has a 0, 1, 2, 3, or 4 in the hundreds column you round to the lesser thousand! For example

8368 rounds to 8000.



rounding to the nearest thousand.4589 rounds to 5000

6900 rounds to 7000

8954 rounds to 9000

Choose the rule:If the number in the hundreds column

is 5, 6, 7, 8, or 9 then round up to the greater thousand.

If the number in the hundreds column is 5, 6, 7, 8, or 9 then round down to the lesser thousand.

A

B

Sorry.Look at the numbers in the hundreds column. Do they cause the number to be rounded to

the lesser thousand or the greater thousand?


• Yes!! You are correct. When a number has a 5, 6, 7, 8, or 9 in the hundreds column you round

to the greater thousand!


Let’s look at the hill again. If you are to round 6300 to the nearest thousand, then your choices are either round back to 6000 or up to

7000. If the car goes up to 6300 and stops, then it will roll back to 6000.

6000

6100

6200

6300

6400

7000

6900

6800

6700

6600

6500

6300 rounds to 6000


Here is another example. If you are to round 2900 to the nearest thousand, then your choices are either round back to 2000 or up to

3000. If the car goes to 2900 and stops, then it will roll to 3000.

2000

2100

2200

2300

2400

3000

2900

2800

2700

2600

2500

2900 rounds to 3000


Now it’s your turn to round to the nearest thousand!

Round 5798

5800

6000

5000

A

C

B

Sorry.

Remember the rules:


round down .


round up.



Round 2045

2000

2050

2100

A

B

C

Sorry.

Remember the rules:


round down .


round up.



Round 9430

8430

8400

9000

A

B

C

Sorry.

Remember the rules:


round down .


round up.


rounding numbers to the nearest ten, hundred, and thousand

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