Rounding Off 3-Digit Numbers

1. What is Rounding Off?

Why do we Round Off numbers?
We round off numbers to make them easier to read and work with. It’s like saying “about how much” instead of giving the exact number.

🔸 For example:
If a number is 492, we can round it off to 500.
If a number is 325, we can round it off to 300.

 2. Rules for Rounding Off to the Nearest 10 and 100

 A. Rounding to the Nearest 10

👉 Steps:

1. Look at the Ones place.
2. If the digit is 0, 1, 2, 3, or 4, round down (keep the Tens same, Ones becomes 0).
3. If the digit is 5, 6, 7, 8, or 9, round up (add 1 to the Tens, Ones becomes 0).
   

Class Examples:

• 87 → Ones = 7 → Round up → 90
• 225 → Ones = 5 → Round up → 230
• 109 → Ones = 9 → Round up → 110
• 43 → Ones = 3 → Round down → 40

B. Rounding to the Nearest 100

👉 Steps:

1. Look at the Tens place.
2. If the digit is 0, 1, 2, 3, or 4, round down (Hundreds stays same, Tens and Ones become 00).
3. If the digit is 5, 6, 7, 8, or 9, round up (add 1 to the Hundreds, Tens and Ones become 00).

Class Examples:

• 342 → Tens = 4 → Round down → 300
• 499 → Tens = 9 → Round up → 500
• 103 → Tens = 0 → Round down → 100
• 367 → Tens = 6 → Round up → 400

3. Practice Questions

✏️ 1. Round these numbers to the nearest 10:
a) 43 → __________
b) 89 → __________
c) 372 → __________
d) 506 → __________
e) 114 → __________

Answers: a) 40  b) 90  c) 370  d) 510  e) 110

✏️ 2. Round these numbers to the nearest 100:
a) 378 → __________
b) 142 → __________
c) 624 → __________
d) 950 → __________
e) 110 → __________

Answers:  a) 400   b) 100   c) 600   d) 1000   e) 100

✏️ 3. Circle the correct rounded number:
a) 267 → 200 or 300?
b) 549 → 500 or 600?
c) 689 → 700 or 600?

Answers: a) 300   b) 500   c) 700

✏️ 4. Write both nearest 10 and nearest 100:
a) 748 → Nearest 10: ______ | Nearest 100: ______
b) 215 → Nearest 10: ______ | Nearest 100: ______
c) 399 → Nearest 10: ______ | Nearest 100: ______

Answers: a) 750 , 700    b) 220, 200   c) 400 , 400