Skip to content
QQuanta KidsBy IIT & ISB Alumni
Sign up
← Back to Numbers & Place Value
1The Millionaire's Mansion2Number Translators3The Multiplier Engine4The Vertical Stack5The Target and the Neighbour6Roman Numerals

Concept 5 of 6

The Target and the Neighbour: Rounding Rules

1

Today's big idea

Check the neighbour, the one digit to the right of the rounding place: 5 or more rounds up, 4 or less stays.

4,728 to the nearest hundred: neighbour 2 is under 5, so it rounds down.

2

How it works

👀 What's going on?

A bicycle costs 4,728 rupees. Nobody says that out loud. They say 'about four thousand seven hundred', and everybody understands them. Rounding is how you find that friendlier number on purpose instead of by feel.

💡 Here's the trick

round DOWN4,728TARGET(hundreds)NEIGHBOUR= 2 (under 5)4,7004,7004,8004,728

Look at the number line above. 4,728 sits between 4,700 and 4,800, and it lands closer to 4,700. To decide that without drawing a line, circle the digit in the rounding place, here the hundreds 7. Then look at the single digit just after it. That one is the neighbour, and here it is a 2.

🪄 How to do it

  1. 1.Circle the digit in the rounding place, the way the 7 is circled in the picture above.
  2. 2.Look at the neighbour, the one digit immediately to its right.
  3. 3.Neighbour 5 or more rounds the target up. Neighbour 4 or less leaves it alone.

✍️ Try it

Round 4,728 to the nearest ten, then round it to the nearest thousand. Do the two answers behave the same way?

For the nearest ten the target is the 2 and the neighbour is 8, so it rounds up to 4,730. For the nearest thousand the target is the 4 and the neighbour is 7, so it rounds up to 5,000. The picture rounded this very number down, because there the neighbour was only a 2.

⚠️ Watch out

You might be thinking you should look at the last digit of the number. Round 4,748 to the nearest hundred and the neighbour is the 4, so it rounds down to 4,700. The 8 sitting on the end looks big, but it never gets a vote.

🌟 Why this matters

Rounding is how you check a bill without adding it properly, or work out whether the money in your pocket will stretch. It also warns you when an answer is wrong, because you already know roughly what it should be.
Exam tip: A quick estimate often rules out two options before you do any real working.

3

Watch me solve one

Quanta solves it

“Watch how I think through one of these — then you try.”

THE PROBLEM

“Round 6,214 to the nearest hundred.”

  1. 1

    Find the TARGET digit

    Nearest hundred → target is the hundreds digit: 2.

  2. 2

    Find the NEIGHBOR digit

    One step right of 2 is 1.

  3. 3

    Apply the rule

    1 is less than 5 → round DOWN.

  4. 4

    Rounded ✓

    6,214 ≈ 6,200

Now you try one — same steps, different story 👇

4

See it in action

⚡ Time to play!

Rounding is a 2-step mission: find the Target digit, check its Neighbor — then round it!

ROUND TO NEAREST THOUSAND

34,812

🎯 Step 1: Tap the TARGET digit — the Thousands digit

5

Quick check

✅ VERIFICATION

Round 6,483 to the nearest hundred.

⚡ Finish the activity above first to answer.

Keep going!

Up next: Roman Numerals

Seven letters that work as numbers: add them, or subtract the small ones.

Concept 6 of 6 →