Rounding Off Numbers Chapter Notes | Mathematics for Class 5 PDF Download

Rounding off is a way to make a number simpler while keeping it close to its original value. We do this by changing the number to a nearby, easier number, often a whole number or a number with fewer digits.

Let’s find out how rounding off helps us in the our day to day life!

Rounding Off Whole Numbers

1. Rounding off to the nearest 10

• If the digit in the ones place is 0, 1, 2, 3, or 4 (i.e. < 5) then replace ones place by ‘0
• 
•  If the digit in the ones place is 5, 6, 7, 8 or 9 (i.e. > 5 or = 5, but < 10), then replace ones digit by ‘0’ and add 1 to the tens place
• 

 2. Rounding off to the nearest 100

• If the digit in the tens place is 0, 1, 2, 3, or 4 (i.e. < 5) then replace ones and tens places by ‘0’
• 
•  If the digit in the tens place is 5, 6, 7, 8 or 9 (i.e. > 5 or = 5, but < 10), then replace ones and tens places by ‘0’ and add 1 to the hundreds place.
• 

3. Rounding off to the nearest 1000

• If the digit in the hundred place is 0, 1, 2, 3, or 4 (i.e. < 5) then replace ones, tens and hundred places by ‘0’.
  
•  If the digit in the hundreds place is 5, 6, 7, 8 or 9 (i.e. > 5 or = 5, but < 10), then replace ones, tens and hundred places by ‘0’ and add 1 to the thousands place.
• 

Rounding Off the Large Numbers

1.  Rounding off to the nearest 10,000

• If the digit in the thousands place is 0, 1, 2, 3, or 4 (i.e. < 5) then replace ones, tens, hundred and thousand places by ‘0’.
• 
•  If the digit in the thousands place is 5, 6, 7, 8 or 9 (i.e. > 5 or = 5, but < 10), then replace ones, tens, hundred and thousands places by ‘0’ and add 1 to the ten thousands place.
• 

2. Rounding off to the nearest 1,00,000

• If the digit in the ten thousands place is 0, 1, 2, 3, or 4 (i.e. < 5) then replace ones, tens, hundred, thousand and ten thousand places by ‘0’.
• 
• If the digit in the ten thousands place is 5, 6, 7, 8 or 9 (i.e. > 5 or = 5, but < 10), then replace ones, tens, hundreds, thousands and ten thousands places by ‘0’ and add 1 to the lakh place.
  
• 

Method to Round Off

Step 1:  Identify the Place Value

• Decide which place value you want to round to (e.g., nearest whole number, nearest ten, nearest hundred).

Step 2:  Look at the Next Digit

• Find the digit immediately to the right of the place value you are rounding to.

Step 3: Apply the Rounding Rules

• If the next digit is 0, 1, 2, 3, or 4
  Round Down: Keep the rounding digit the same and change all digits to the right to zero (or remove them).
• Example:
  34 rounds to 30 (look at 4).
  57 rounds to 60 (look at 7).
• If the next digit is 5, 6, 7, 8, or 9
  Round Up: Increase the rounding digit by 1 and change all digits to the right to zero (or remove them).
• Example:
  42 rounds to 40 (look at 2).
  86 rounds to 90 (look at 6).

Examples

Example 1: Round 22 to the nearest ten.
Ans: 20 

Sol:
Step 1: Look at the digit in the ones place (2).

Step 2: Since 2 is less than 5, we round down.

Therefore the answer rounds down to 20.

Example 2: Round 236 to the nearest hundred.
Ans: 200

Sol:
Step 1: Look at the digit in the tens place (3).
Step 2: Since 3 is less than 5, we round down.
Therefore the answer rounds down to 200.

Example 3: Round 12,345 to the nearest thousand.
Ans: 12000

Sol:
Step 1: Look at the digit in the hundreds place (3).
Step 2: Since 3 is less than 5, we round down.
Therefore 12,345 rounds down to 12,000.

Example 4: Round 876,543 to the nearest hundred thousand.
Ans: 900,000

Sol:
Step 1: Look at the digit in the ten thousand place (7).
Step 2: Since 7 is 5 or more, we round up.
Therefore , 876,543 rounds up to 900,000.