RoundRound- to find the - to find the nearest value of a nearest value of a

number based on a number based on a given place value.given place value.

Memorize this Poem

Find your number.Look right next door.4 or less, just ignore.5 or more, add 1 more.

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Find your number.

37

Round to the nearest tens place

Look right next door.

304

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: If the number is 5 or greater than add 1 to the circled number.

Step 5: All numbers to the right of the circled number become zeros.

7

Round to the nearest tens place

4 or less, just ignore.

7 is not less

than 4

5 or more, add 1 more.

3 + 1 = 4

37 rounded to the nearest tens place is

4030 4037

37 is closer to 40 on the number line.

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Find your number.

52

Round to the nearest tens place

Look right next door.

50

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: All numbers to the right of the circled number become zeros.

2

Round to the nearest tens place

4 or less, just ignore.

2 is less

than 4

Just Ignore!

52 rounded to the nearest tens place is

5050 6052

52 is closer to 50 on the number line.

Find your number.Look right next door.

47

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Round to the nearest thousands place.

, 63

000463

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: All numbers to the right of the circled number become zeros.

4 or less, just ignore.

4 = 4Just Ignore!

7,

Round to the nearest thousands place.

7,463 rounded to the nearest thousands

place is7,0007,000 8,0007,463

7,463 is closer to 7,000 on the number line.

5

Find your number.

68

Round to the nearest tenths place.

Look right next door.

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

.

5

4 or less, just ignore.5 or more, add 1 more.

8 is not less than

4

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: If the number is 5 or greater than add 1 to the circled number.

Step 5: All numbers to the right of the circled number become zeros.

6 + 1 = 7

6870.

Round to the nearest tenths place.

5.68 rounded to the nearest tenths place

is5.75.6 5.75.68

5.68 is closer to 5.7 on the number line.

Find your number.

Round to the nearest hundredths place.

Look right next door.

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

46. 58

08564

4 or less, just ignore.5 or more, add 1 more.

8 is not less than

4

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: If the number is 5 or greater than add 1 to the circled number.

Step 5: All numbers to the right of the circled number become zeros.

5 + 1 = 6

6.

Round to the nearest hundredths place.

6.458 rounded to the nearest hundredths place

is6.46

6.45 6.46

6.458

6.458 is closer to 6.46 on the number line.

Find your number.

Round to the nearest thousandths place.

Look right next door.

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

94. 97

749095. 00

4 or less, just ignore.5 or more, add 1 more.

7 is not less than

4

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: If the number is 5 or greater than add 1 to the circled number.

Step 5: All numbers to the right of the circled number become zeros.

9 + 1 = 10

10 thousandths = 1 hundredths.

Time to regroup!

+1

Round to the nearest thousandths place.

9 + 1 = 10

10 hundredths = 1 tenth.

Time to regroup!

4 + 1 = 5

.4997 rounded to the nearest thousandths

place is.5

.499 .5

.4997

.4997 is closer to .5 on the number line.

Find your number.

Round to the nearest dollar.

Look right next door.

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

5$ 72.

00657

4 or less, just ignore.5 or more, add 1 more.

7 is not less than

4

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: If the number is 5 or greater than add 1 to the circled number.

Step 5: All numbers to the right of the circled number become zeros.

5 + 1 = 6

Round to the nearest dollar.

$ 2.

$5.72 rounded to the nearest dollar is

$6.00$5.00 $6.00$5.72

$5.72 is closer to $6.00 on the number line.

3

Find your number.Look right next door.

9$

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Round to the nearest ten cents.

. 4

0

Step 1: Circle the digit in the place that you must round to.

Step 2: Draw an arrow to the place on the right.

Step 3: If the number is four or less, then the circled number stays the same.

Step 4: All numbers to the right of the circled number become zeros.

4 or less, just ignore.

4 = 4

39$

Round to the nearest ten cents.

.Just

Ignore!

4

$9.34 rounded to the nearest ten cents is

$9.30$9.30 $9.40$9.34

$9.34 is closer to $9.30 on the number line.

1. …nearest ten 5442. …nearest hundred 9,5643. …nearest million 12,897,8764. …nearest thousand 5,3895. …nearest hundred thousand

167,9006. …nearest ten cents $8.35 7. …nearest thousand 5,785,965 8. …nearest dollar $56.399. …nearest hundred 935,987

1. 5402. 9,6003. 13,000,0004. 5,0005. 200,0006. $8.407. 5,786,0008. $56.009. 936,000

Round to the…

1. …nearest tenth 1.242. …nearest hundredth 12.7653. …nearest hundredth 0.4344. …nearest tenth 0.3675. …nearest hundredth 8.5986. …nearest tenth 2.854 7. …nearest tenth 156.78 8. …nearest hundredth 3.5329. …nearest tenth 0.876

1. 1.22. 12.773. 0.434. 0.45. 8.66. 2.97. 156.88. 3.539. 0.9

Round to the…

EstimateEstimate- to find a - to find a number that is close number that is close to the exact answer.to the exact answer.

When to use estimation…

When an exact answer is not needed.

When you need to compute a problem quickly.

To check your work.

© 2007 M. Tallman

486 + 130

5 1+ = 6Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each addend to the hundreds place.

00000 0

The actual answer is 616,

so our estimation is

pretty accurate.

The actual answer is 616,

so our estimation is

pretty accurate.

Step 3: Now you can add 500 and 100 mentally.

© 2007 M. Tallman

5,387 + 386

5,000 400+ =5,400

Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round the first addend to the thousands place and the second addend to the hundreds place.

Step 3: Now you can add 5,000 and 400 mentally.

The actual answer is 5,773, so our estimation is pretty

accurate

Rounding Tip: The lower the place, the more accurate the answer. However, if you round too low, your problem may be more difficult to solve.

Rounding Tip: The lower the place, the more accurate the answer. However, if you round too low, your problem may be more difficult to solve.

Rounding Tip: The higher the place, the easier your problem will be to solve. However, your answer may not be as accurate.

Rounding Tip: The higher the place, the easier your problem will be to solve. However, your answer may not be as accurate.

© 2007 M. Tallman

5,400

5,387 + 386

5,000 400+ =5,400

Step 1: Rounding is always first. Decide which place to round to.

Step 3: Now you can add 5,400 and 400 mentally.

5,800

Step 2: Round the first addend to the thousands place and the second addend to the hundreds place.

© 2007 M. Tallman

44,897 + 26,578

40,000 30,000+ =70,000Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each addend to the ten thousands place.

Step 3: Now you can add 40,000 and 30,000 mentally.

The actual answer is

71,475, so our estimation is

pretty accurate.

The actual answer is

71,475, so our estimation is

pretty accurate.

© 2007 M. Tallman

$8.67 + $6.75

$9.00 $7.00+ =$16.00Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each addend to the nearest dollar.

Step 3: Now you can add $9.00 and $7.00, mentally.

The actual answer is

$15.42, so our estimation is

pretty accurate.

The actual answer is

$15.42, so our estimation is

pretty accurate.

© 2007 M. Tallman

17.4 + 4.8

17 5+ = 22Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each addend to the nearest whole number.

The actual answer is 22.2,

so our estimation is

pretty accurate.

The actual answer is 22.2,

so our estimation is

pretty accurate.

Step 3: Now you can add 17 and 5 mentally.

© 2007 M. Tallman

9.7 + 2.8

10 3+ = 13Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each addend to the nearest whole number.

The actual answer is 12.5,

so our estimation is

pretty accurate.

The actual answer is 12.5,

so our estimation is

pretty accurate.

Step 3: Now you can add 10 and 3 mentally.

© 2007 M. Tallman

42.8 + 6.3

43 6+ = 49Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each addend to the nearest whole number.

The actual answer is 49.1,

so our estimation is

pretty accurate.

The actual answer is 49.1,

so our estimation is

pretty accurate.

Step 3: Now you can add 43 and 6 mentally.

© 2007 M. Tallman

1. $21.89 + $6.78

5,000

600100+500=

1,200500 +700 =

$27.00

4. 4,897 + 598

3. 145 + 467

Estimate Each Sum

2. 467 + 721

$20.00+$7.00=

5,600+600 =

© 2007 M. Tallman

$103.00

5. 13.56 + 4.4

$5.00

$112.00$9.00+ =

171 + 16 =

18

8. $4.77 + $28.70

7. $9.33 + $102.5

6. 0.78 + 15.89

14 + 4 =

$34.00+$29.00 =

Estimate Each Sum

© 2007 M. Tallman

$2.00

9. $3.26 + $14.67

0

$32.00$30.00 + =

396 + 33 =

$18.00

12. 0.23 + 12.67

11. $29.53 + $2.45

10. 6.42 + 33.31

$3.00+$15.00 =

13+ 13 =

Estimate Each Sum

© 2007 M. Tallman

© 2007 M. Tallman

496 - 112

500 100- = 400

Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each number to the hundreds place.

Step 3: Now you can subtract 100 from 500, mentally.

The actual answer is 384,

so our estimation is

pretty accurate.

The actual answer is 384,

so our estimation is

pretty accurate.

© 2007 M. Tallman

5,251 - 896

5,000 900- =4,100

Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round the first addend to the thousands place and the second addend to the hundreds place.

Step 3: Now you can subtract 900 from 5,000, mentally.

The actual answer is 4,355, so our estimation is pretty

accurate

Rounding Tip: The lower the place, the more accurate the answer. However, if you round too low, your problem may be more difficult to solve.

Rounding Tip: The lower the place, the more accurate the answer. However, if you round too low, your problem may be more difficult to solve.

Rounding Tip: The higher the place, the easier your problem will be to solve. However, your answer may not be as accurate.

Rounding Tip: The higher the place, the easier your problem will be to solve. However, your answer may not be as accurate.

© 2007 M. Tallman

52,187 - 18,978

50,000 20,000- =30,000Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each addend to the ten thousands place.

Step 3: Now you can subtract 20,000 from 50,000, mentally.

The actual answer is

33,209, so our estimation is

pretty accurate.

The actual answer is

33,209, so our estimation is

pretty accurate.

© 2007 M. Tallman

$19.67 - $6.35

$20.00 $6.00- =$14.00Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round $19.67 to the nearest ten dollars. Round $6.35 to the nearest dollar.

Step 3: Now you can subtract $6.00 from $20.00, mentally.

The actual answer is

$13.32, so our estimation is

pretty accurate.

The actual answer is

$13.32, so our estimation is

pretty accurate.

© 2007 M. Tallman

17.4 - 4.8

17 5- = 12Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each number to the nearest whole number.

The actual answer is 12.6,

so our estimation is

pretty accurate.

The actual answer is 12.6,

so our estimation is

pretty accurate.

Step 3: Now you can subtract 17 and 5 mentally.

© 2007 M. Tallman

15.7 - 7.8

16 8- = 8Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each number to the nearest whole number.

The actual answer is 7.9,

so our estimation is

pretty accurate.

The actual answer is 7.9,

so our estimation is

pretty accurate.

Step 3: Now you can subtract 18 and 8 mentally.

© 2007 M. Tallman

45.8 - 6.3

46 6- = 40Step 1: Rounding is always first. Decide which place to round to.

Step 2: Round each number to the nearest whole number.

The actual answer is 39.5,

so our estimation is

pretty accurate.

The actual answer is 39.5,

so our estimation is

pretty accurate.

Step 3: Now you can subtract 46 and 6 mentally.

© 2007 M. Tallman

1. $21.89 - $6.78

5,000

200700- 500=

300500 - 200 =

$13.00

4. 4,897 - 898

3. 745 - 467

Estimate Each Difference

2. 467 - 221

$20.00 - $7.00=

4,100- 900 =

© 2007 M. Tallman

$3.00

5. 13.56 - 4.4

$15.00

$6.00$9.00 - =

410 - 6 =

10

8. $14.77 - $8.70

7. $9.33 - $2.59

6. 9.78 - 5.89

14 - 4 =

$6.00- $9.00 =

Estimate Each Difference

© 2007 M. Tallman

$2.00

9. $23.26 - $14.67

12

$28.00$30.00 - =

3366 - 33 =

$8.00

12. 12.23 - 0.67

11. $29.53 - $2.45

10. 66.42 - 33.31

$23.00 - $15.00 =

11- 1 =

Estimate Each Difference

Points to Keep in Mind Points to Keep in Mind When EstimatingWhen Estimating

The The higher the placehigher the place is that you round is that you round to, the to, the easiereasier the estimation will be. the estimation will be. Your answer may be Your answer may be less accurateless accurate though.though.

The The lower the placelower the place that you round to, that you round to, the the more difficultmore difficult your estimation will your estimation will be. Your answer will be be. Your answer will be more accurate more accurate thoughthough..

Always ask yourself, “What makes the Always ask yourself, “What makes the most sense?”.most sense?”.