What is the rule for rounding to the nearest 10?

Look at the ones digit. If it is 5 or more, round the tens up; if it is 4 or less, keep the tens the same. So 67 rounds to 70, while 63 rounds to 60.

Which digit do I look at when rounding to the nearest 100 or 1000?

For the nearest 100, check the tens digit; for the nearest 1000, check the hundreds digit. The chosen digit decides whether you round up or stay, and all the digits to its right become zeros.

What happens when a number ends in 5, like 45?

In Singapore primary school the convention is that 5 rounds up, so 45 rounds to 50 to the nearest ten. The digit being exactly 5 still counts as "5 or more".

Why do children learn rounding in primary school?

Rounding builds number sense and lets pupils estimate quickly and check whether an answer is reasonable. It is also the foundation for later topics like estimating sums, working with decimals, and significant figures.

What is the difference between rounding and estimating?

Rounding changes one number to a nearby tidy value. Estimating uses rounded numbers to get an approximate answer to a calculation — for example, rounding 38 and 51 to 40 and 50 to estimate their sum as about 90.

Rounding to the Nearest 10, 100, 1000

Math Interactive lesson Free to play

Rounding to the nearest 10, 100 or 1000 is a way of replacing a number with the closest "tidy" multiple of ten, a hundred or a thousand, so it is quicker to say, estimate with, and check. For example, 38 rounds to 40 to the nearest ten, and 352 rounds to 400 to the nearest hundred.

It matters because real life rarely needs exact figures: a crowd of "about 5,000", a price of "roughly $20", or a trip of "around 300 km" are all rounded values. In Singapore's MOE syllabus, rounding underpins estimation, sensible answer-checking, and later work with decimals and significant figures.

The key ideas a learner grasps are: every number sits between two multiples, and you round to the nearer one; a number line shows which side it falls on; and the shortcut "5 or more rounds up, 4 or less stays" lets you decide by reading just one digit. Which digit you check depends on the place you are rounding to — ones for the nearest 10, tens for the nearest 100, and hundreds for the nearest 1000.

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What this Spark covers

What is rounding?

🎯 Let's learn Rounding! Rounding means finding a close, tidy number that is easier to say and use. Imagine your class has 38 students. You might say: "about 40" 40 is the nearest tidy ten — it's easy to remember and good enough for a quick answer. In this Spark you'll round to the nearest 10, 100, and 1000. Tap Next to begin! 👉
The number line trick

Which ten is closer? Every number sits between two tens. Round to whichever ten is nearer. Where should 73 round to? Tap the closer ten. 73 70 80 73 is between 70 and 80. Which is closer? Tip: count the gaps — 73 is only 3 away from 70, but 7 away from 80.
The 5-or-more rule

The magic rule ✨ You don't always need a number line. Just look at one digit — the one to the right of where you're rounding. 👉 5, 6, 7, 8, 9 → round UP ⬆️ 👉 0, 1, 2, 3, 4 → stay DOWN (keep the same) ⬇️ Let's round 246 to the nearest ten. The decider is the pink digit. Tap it! 2 4 6 Tap the pink 6 to find out what to do.
Round to the nearest 10

Your turn: nearest 10 Look at the ones digit (the last one). Is it 5 or more? Then round up! 67 Round to the nearest 10 Pick the closest tidy ten.
Round to the nearest 100

Nearest 100 🏯 Now we cover up the last two digits and look at the tens digit to decide. Round 352 to the nearest hundred: 1Find the hundreds: 352 → between 300 and 400. 2Decider = the tens digit: 352 → it's 5. 35 means round UP → 400! 🎉 418 Round to the nearest 100 Check the tens digit to decide.
Round to the nearest 1000

Nearest 1000 🚀 Same idea, bigger number! For the nearest thousand, the decider is the hundreds digit. Round 4621. Tap the hundreds digit to reveal the decision. 4 6 2 1 Tap the pink 6 — is it 5 or more? 7340 Round to the nearest 1000 Look at the hundreds digit (the 2nd one).
You did it!

🏆 Brilliant work! You're now a rounding champion! Here's the whole trick in one box: 1️⃣ Decide what to round to (10, 100 or 1000). 2️⃣ Look at the next digit to the right — the decider. 3️⃣ 5 or more → round up. 4 or less → stay the same. 4️⃣ Turn the digits after it into zeros. ✅ Quick recap: ✓73 → nearest 10 = 70 ✓352 → nearest 100 = 400 ✓4621 → nearest 1000 = 5000 Keep practising and you'll round in your head super fast! 🌟

Frequently asked questions

What is the rule for rounding to the nearest 10?: Look at the ones digit. If it is 5 or more, round the tens up; if it is 4 or less, keep the tens the same. So 67 rounds to 70, while 63 rounds to 60.
Which digit do I look at when rounding to the nearest 100 or 1000?: For the nearest 100, check the tens digit; for the nearest 1000, check the hundreds digit. The chosen digit decides whether you round up or stay, and all the digits to its right become zeros.
What happens when a number ends in 5, like 45?: In Singapore primary school the convention is that 5 rounds up, so 45 rounds to 50 to the nearest ten. The digit being exactly 5 still counts as "5 or more".
Why do children learn rounding in primary school?: Rounding builds number sense and lets pupils estimate quickly and check whether an answer is reasonable. It is also the foundation for later topics like estimating sums, working with decimals, and significant figures.
What is the difference between rounding and estimating?: Rounding changes one number to a nearby tidy value. Estimating uses rounded numbers to get an approximate answer to a calculation — for example, rounding 38 and 51 to 40 and 50 to estimate their sum as about 90.

Rounding to the Nearest 10, 100, 1000

What this Spark covers

Frequently asked questions

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