Rounding to 10, 100, 1000
Round any number to the nearest 10, 100, or 1000
What a learner can do afterwards
- Round 4,367 to the nearest 10 (4,370), 100 (4,400), and 1000 (4,000)
- Explain the rounding rule using a number line (which multiple is closer)
- Apply rounding to estimate calculations
The lesson
Rounding changes a number to the nearest 10, 100, or 1000, so it is easier to work with. You already know place value, so you know which digit sits in the ones, tens, hundreds, and thousands spot. Rounding uses those digits to find the closest round number.
Round 4,367. To the nearest 10, look at the ones digit, 7. It is 5 or more, so 4,367 rounds up to 4,370. To the nearest 100, look at the tens digit, 6. Round up to 4,400. To the nearest 1000, look at the hundreds digit, 3. Round down to 4,000.
Find the digit just to the right of the place you are rounding to. If it is 5, 6, 7, 8, or 9, round up. If it is 0, 1, 2, 3, or 4, round down. Every digit after that becomes zero.
Rounding lets you estimate fast. To add 4,367 and 2,850, round each to the nearest 1000 first: 4,000 + 3,000 = 7,000. That is close to the real answer and quick to check in your head.
Look at the digit right after the place you're rounding to: 5 or more rounds up, 4 or less rounds down, and everything after turns to zero.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.