Rounding Numbers to the Nearest Ten, Hundred, or Thousand and Adding Them

Introduction: Rounding numbers can make math much easier, especially when working with addition. By rounding numbers to the nearest ten, hundred, or thousand, we can quickly estimate sums and find answers. Let's break it down step-by-step, starting with rounding to the nearest ten, then moving on to the hundred and thousand places.

Rounding to the Nearest Ten and Adding Rounded Numbers

How to Round to the Nearest Ten

1. Look at the Ones Place - When rounding to the nearest ten, focus on the ones digit (the last number).
2. Decide to Round Up or Down:
   • If the ones digit is 5 or more, round up.
   • If the ones digit is 4 or less, round down.

Example Problem

Round and Add 76 and 43 to the Nearest Ten:

1. Round Each Number:
   • 76: Look at the ones digit (6). Since 6 is 5 or more, we round up to 80.
   • 43: Look at the ones digit (3). Since 3 is less than 5, we round down to 40.
2. Add the Rounded Numbers: 80 + 40 = 120

Answer: By rounding to the nearest ten, we estimated the sum as 120.

More Examples

• Round and add 57 and 34: 57 rounds to 60, and 34 rounds to 30. 60 + 30 = 90
• Round and add 112 and 79: 112 rounds to 110, and 79 rounds to 80. 110 + 80 = 190

Rounding to the Nearest Hundred and Adding Rounded Numbers

How to Round to the Nearest Hundred

1. Look at the Tens Place - When rounding to the nearest hundred, focus on the tens digit.
2. Decide to Round Up or Down:
   • If the tens digit is 5 or more, round up.
   • If the tens digit is 4 or less, round down.

Example Problem

Round and Add 364 and 528 to the Nearest Hundred:

1. Round Each Number:
   • 364: Look at the tens digit (6). Since 6 is 5 or more, round up to 400.
   • 528: Look at the tens digit (2). Since 2 is less than 5, round down to 500.
2. Add the Rounded Numbers: 400 + 500 = 900

Answer: By rounding to the nearest hundred, we estimated the sum as 900.

More Examples

• Round and add 245 and 678: 245 rounds to 200, and 678 rounds to 700. 200 + 700 = 900
• Round and add 825 and 365: 825 rounds to 800, and 365 rounds to 400. 800 + 400 = 1,200

Rounding to the Nearest Thousand and Adding Rounded Numbers

How to Round to the Nearest Thousand

1. Look at the Hundreds Place - When rounding to the nearest thousand, focus on the hundreds digit.
2. Decide to Round Up or Down:
   • If the hundreds digit is 5 or more, round up.
   • If the hundreds digit is 4 or less, round down.

Example Problem

Round and Add 3,672 and 8,459 to the Nearest Thousand:

1. Round Each Number:
   • 3,672: Look at the hundreds digit (6). Since 6 is 5 or more, round up to 4,000.
   • 8,459: Look at the hundreds digit (4). Since 4 is less than 5, round down to 8,000.
2. Add the Rounded Numbers: 4,000 + 8,000 = 12,000

Answer: By rounding to the nearest thousand, we estimated the sum as 12,000.

More Examples

• Round and add 4,320 and 5,780: 4,320 rounds to 4,000, and 5,780 rounds to 6,000. 4,000 + 6,000 = 10,000
• Round and add 9,452 and 2,361: 9,452 rounds to 9,000, and 2,361 rounds to 2,000. 9,000 + 2,000 = 11,000

Conclusion

Rounding to the nearest ten, hundred, or thousand can simplify addition and give us quick estimates. Practice these steps to become more comfortable with rounding and adding rounded numbers!

Rounding Numbers for Subtraction: Nearest Ten, Hundred, and Thousand

Rounding numbers is a valuable skill that simplifies math, especially for subtraction. When we round numbers to the nearest ten, hundred, or thousand, we can estimate answers quickly and make math easier. Let’s walk through how to round and subtract with examples!

Rounding to the Nearest Ten and Subtracting

How to Round to the Nearest Ten

• Look at the Ones Place: When rounding to the nearest ten, check the ones digit (the last number).
• Round Up or Down:
  • If the ones digit is 5 or more, round up.
  • If the ones digit is 4 or less, round down.

Example Problem

Round and Subtract 76 and 43 to the Nearest Ten:

1. Round Each Number:
   • 76: The ones digit is 6. Since 6 is 5 or more, round up to 80.
   • 43: The ones digit is 3. Since 3 is less than 5, round down to 40.
2. Subtract the Rounded Numbers: 80 - 40 = 40

Answer: By rounding to the nearest ten, we estimated the difference as 40.

More Examples

• Round and subtract 57 and 34:
  • 57 rounds to 60, and 34 rounds to 30.
  • 60 - 30 = 30
• Round and subtract 112 and 79:
  • 112 rounds to 110, and 79 rounds to 80.
  • 110 - 80 = 30

Rounding to the Nearest Hundred and Subtracting

How to Round to the Nearest Hundred

• Look at the Tens Place: When rounding to the nearest hundred, check the tens digit.
• Round Up or Down:
  • If the tens digit is 5 or more, round up.
  • If the tens digit is 4 or less, round down.

Example Problem

Round and Subtract 364 and 528 to the Nearest Hundred:

1. Round Each Number:
   • 364: The tens digit is 6. Since 6 is 5 or more, round up to 400.
   • 528: The tens digit is 2. Since 2 is less than 5, round down to 500.
2. Subtract the Rounded Numbers: 500 - 400 = 100

Answer: By rounding to the nearest hundred, we estimated the difference as 100.

More Examples

• Round and subtract 245 and 678:
  • 245 rounds to 200, and 678 rounds to 700.
  • 700 - 200 = 500
• Round and subtract 825 and 365:
  • 825 rounds to 800, and 365 rounds to 400.
  • 800 - 400 = 400

Rounding to the Nearest Thousand and Subtracting

How to Round to the Nearest Thousand

• Look at the Hundreds Place: When rounding to the nearest thousand, check the hundreds digit.
• Round Up or Down:
  • If the hundreds digit is 5 or more, round up.
  • If the hundreds digit is 4 or less, round down.

Example Problem

Round and Subtract 3,672 and 8,459 to the Nearest Thousand:

1. Round Each Number:
   • 3,672: The hundreds digit is 6. Since 6 is 5 or more, round up to 4,000.
   • 8,459: The hundreds digit is 4. Since 4 is less than 5, round down to 8,000.
2. Subtract the Rounded Numbers: 8,000 - 4,000 = 4,000

Answer: By rounding to the nearest thousand, we estimated the difference as 4,000.

More Examples

• Round and subtract 4,320 and 5,780:
  • 4,320 rounds to 4,000, and 5,780 rounds to 6,000.
  • 6,000 - 4,000 = 2,000
• Round and subtract 9,452 and 2,361:
  • 9,452 rounds to 9,000, and 2,361 rounds to 2,000.
  • 9,000 - 2,000 = 7,000

Conclusion

Rounding to the nearest ten, hundred, or thousand can simplify subtraction and help us find estimates quickly. Try practicing these steps to become confident with rounding and subtracting rounded numbers!

Rounding Numbers to the Nearest Ten, Hundred, or Thousand and Multiplying Them

Introduction

Rounding numbers can make math much easier, especially when working with multiplication. By rounding numbers to the nearest ten, hundred, or thousand, we can quickly estimate products and find answers. Let's break it down step-by-step, starting with rounding to the nearest ten, then moving on to the hundred and thousand places.