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4th Grade · 4.NBT.A.3

Rounding to the nearest thousand in 4th grade

Rounding to the nearest thousand means replacing a number with the closest multiple of 1,000, such as 7,000 or 8,000. In 4th grade, your child rounds numbers up to a million to any place: tens, hundreds, thousands and more. The point of rounding is a quick, sensible estimate.

What the standard says

The official Common Core wording, quoted exactly. The plain version follows.

4.NBT.A.3 Use place value understanding to round multi-digit whole numbers to any place.

What it means, in plain words

Rounding gives a number that is close to the real one and easier to work with. A multiple of 1,000 is a number such as 5,000, 12,000 or 300,000. Each one ends in at least three zeros.

Rounding to the nearest thousand takes two steps. First, find the two thousands the number sits between: 6,240 sits between 6,000 and 7,000. Then decide which one is closer. The halfway point is 6,500, and 6,240 is below it, so 6,240 rounds to 6,000. A number exactly at the halfway point rounds up.

Many classes also teach a shortcut: look at the hundreds digit, and round up if it is 5 or more. The shortcut works, but a child who only knows the rule has no sense of size to catch a wrong answer. The same two steps work for rounding to the nearest ten, hundred or ten thousand.

Your child should be able to:

  • Name the two thousands a number sits between
  • Find the halfway point and decide which thousand is closer
  • Round numbers up to 1,000,000 to the nearest ten, hundred, thousand or ten thousand
  • Use rounded numbers to check whether an answer makes sense

Example

Round 27,618 to the nearest thousand.

  1. 27,618 sits between 27,000 and 28,000.
  2. The halfway point is 27,500.
  3. 27,618 is more than 27,500, so it is closer to 28,000.
  4. 27,618 rounded to the nearest thousand is 28,000.

Example

A family drives 3,812 miles one summer and 4,295 miles the next. About how many miles is that in all?

  1. Round each number to the nearest thousand: 3,812 rounds to 4,000, and 4,295 rounds to 4,000.
  2. 4,000+4,000=8,0004{,}000 + 4{,}000 = 8{,}000
  3. The family drove about 8,000 miles. The exact total, 8,107 miles, is close to that, so the estimate makes sense.

Where children usually get stuck

  • Asked to round 5,486 to the nearest thousand, your child writes 5,490 or 5,500.

    The child learned "look next door, 5 or more round up" and looked next to the wrong digit. The rule carries no sense of size, so nothing signals the mistake.

    What helps. Ask which two thousands 5,486 sits between. Write 5,000 and 6,000 at the ends of a line and mark the number on it. The answer has to be one of those two, and here it is 5,000.

  • Your child rounds 3,468 in steps: 3,470, then 3,500, then 4,000.

    Each step looks like a correct round, but every step moves the number further from where it started. 3,468 is closer to 3,000 than to 4,000.

    What helps. Round in one step only. Put 3,000, 3,500 and 4,000 on a number line and place 3,468 on it. It is below the halfway point, so it rounds to 3,000.

  • Rounding 52,730 to the nearest thousand, your child writes 53,730 or just 53.

    The child changes the thousands digit but forgets that every place to its right becomes zero, or drops those places.

    What helps. Ask your child to say the rounded number out loud: fifty-three thousand. Then ask how many hundreds, tens and ones that has. There are none, so those places are all zeros: 53,000.

Try four practice questions

Real 4th grade questions from our question bank, easiest first. Answer them right here, check each one, and see a worked solution for any question.

  1. 1Warm-up
    248 rounded to the nearest ten=250\displaystyle 24\textcolor{#c94c7c}{8} \text{ rounded to the nearest ten} = 250
    The pink digit decides how the number rounds. Which sentence correctly explains why 248 rounds to 250?
    A
    The ones digit is 8. Since 8 is greater than 5, the tens digit stays at 4 and the digits to its right become 0, so 248 rounds down to 240.
    B
    The tens digit is 4. Since 4 is less than 5, the tens digit stays at 4 and the digits to its right become 0, so 248 rounds down to 240.
    C
    The ones digit is 8. Since 8 is greater than 5, the tens digit increases by 1 and the digits to its right become 0, so 248 rounds up to 250.
    D
    The ones digit is 8. Since 8 is greater than 5, the ones digit increases by 1 and the digits to its right become 0, so 248 rounds up to 249.
    Show the answer and how to solve it

    The correct explanation looks at the ones digit (8), recognizes that 8 is greater than 5, and concludes that 248 rounds up to 250.

    1. 1Look at the rounding fact. The digit in pink is the ones digit (8). Because we are rounding to the nearest ten, the ones digit — the digit immediately to the right of the tens place — is the deciding digit.
    2. 2Compare the deciding digit to 5. The ones digit is 8, and 8 is greater than 5. The rounding rule says: when the deciding digit is greater than 5, we round UP.
    3. 3Rounding up means the tens digit increases by 1 (from 4 to 5), and every digit to the right of the tens place becomes 0:
    4. 4The correct explanation is the one that uses the ones digit (8), recognizes that 8 is greater than 5, and concludes that 248 rounds up to 250.

    Common mistake. A common mistake is using the wrong digit — for example, looking at the tens digit itself (4) instead of the digit immediately to its right (8). When rounding to the nearest ten, the ones digit is the one that decides up or down.

    The idea underneath. When rounding to a place, only the digit immediately to its right decides up or down. Once the direction is set, every digit below the rounding place becomes 0 — not just some of them.

  2. 2On level
    4,673 rounded to the nearest hundred is 4,700. Two students explained why.
    AThe tens digit is 7, which is at least 5, so we round up to 4,700.
    BThe halfway point between 4,600 and 4,700 is 4,650, and since 4,673 is less than 4,650, round up to 4,700.
    Which statement best describes the explanations?
    A
    Only Explanation A is correct.
    B
    Only Explanation B is correct.
    C
    Both explanations are correct.
    D
    Neither explanation is correct.
    Show the answer and how to solve it

    Only Explanation A is correct. The digit rule (the tens digit is 7, which is at least 5, so round up) properly explains why 4,673 rounds to 4,700. Explanation B's halfway-point reasoning has the inequality backwards: 4,673 is greater than 4,650, not less than it.

    1. 1Check Explanation A. To round 4,673 to the nearest hundred, look at the digit one place to the right of the hundreds place — that is the tens digit. The tens digit of 4,673 is 7. Since 7 is at least 5, we round up to 4,700. Explanation A's reasoning is correct.
    2. 2Check Explanation B. The halfway point between 4,600 and 4,700 is 4,650 — that part is correct. But Explanation B then says '4,673 is less than 4,650.' Compare the numbers: 4,673 is actually greater than 4,650, not less than it. The inequality is backwards, so Explanation B's reasoning is incorrect.
    3. 3Only Explanation A correctly explains why 4,673 rounds to 4,700. The correct option is the one stating only Explanation A is correct.

    Common mistake. A common mistake is checking only the conclusion ('round up to 4,700') in each explanation. Both conclusions match the claim, so students may accept both — without verifying that Explanation B's comparison of 4,673 and 4,650 is reversed.

    The idea underneath. An explanation is only correct if every step of the reasoning is true. A correct conclusion can come from incorrect reasoning. Both the digit rule and the halfway-point method are valid ways to round, but each step must be applied correctly.

  3. 3On level
    A bus company drove 82,341 miles last year. About how many miles did the company drive, rounded to the nearest ten-thousand?
    A
    80,000
    B
    82,000
    C
    90,000
    D
    100,000
    Show the answer and how to solve it

    The answer is 80,000. To round 82,341 to the nearest ten-thousand, look at the thousands digit (2). Since 2 is less than 5, round down, keeping the ten-thousands digit at 8.

    1. 1Find the digit in the ten-thousands place. In 82,341, the ten-thousands digit is 8.
    2. 2Look at the digit to the right of the ten-thousands place — the thousands digit. It is 2.
    3. 3Since 2 is less than 5, round down. The ten-thousands digit stays at 8, and every digit to the right becomes 0.

    Common mistake. A common mistake is rounding up to 90,000 by ignoring the deciding digit. The deciding digit is the thousands digit (2) — the digit to the RIGHT of the ten-thousands place — and because 2 is less than 5, the ten-thousands digit stays at 8, giving 80,000.

    The idea underneath. When you round to a place, the digit IMMEDIATELY to the right is the only one that decides whether to round up or down — ask yourself: is that digit 5 or more?

  4. 4Stretch
    Select all numbers that round to 6,000 when rounded to the nearest thousand.
    A
    5,499
    B
    5,500
    C
    6,100
    D
    6,499
    E
    6,500
    F
    7,300
    Show the answer and how to solve it

    The numbers 5,500, 6,100, and 6,499 all round to 6,000 when rounded to the nearest thousand. They fall in the range from 5,500 up through 6,499. The other three numbers — 5,499, 6,500, and 7,300 — round to 5,000 or 7,000 instead.

    1. 1First, find the range of numbers that round to 6,000 when rounded to the nearest thousand. The halfway point below 6,000 is 5,500, and the halfway point above 6,000 is 6,500. Numbers from 5,500 up through 6,499 all round to 6,000.
    2. 2Now check each number to see if it falls in the range from 5,500 to 6,499.
    3. 3Check 5,499. It is one less than 5,500, so it falls just below the range. 5,499 rounds DOWN to 5,000, not 6,000.
    4. 4Check 5,500. It is exactly the lower halfway point — the first value in the range. 5,500 rounds to 6,000. This number IS correct.
    5. 5Check 6,100. It is between 5,500 and 6,499, well inside the range. 6,100 rounds to 6,000. This number IS correct.
    6. 6Check 6,499. It is the last whole number in the range, one below the upper halfway. 6,499 rounds to 6,000. This number IS correct.
    7. 7Check 6,500. This is exactly the upper halfway point. When a number is exactly halfway, it rounds UP, so 6,500 rounds to 7,000, not 6,000.
    8. 8Check 7,300. It is greater than 6,499, so it is above the range. 7,300 rounds UP to 7,000, not 6,000.
    9. 9The numbers that round to 6,000 are 5,500, 6,100, and 6,499.

    Common mistake. A common mistake is including 6,500 because it appears close to 6,000. But when a number is exactly the upper halfway point, it rounds UP to the next thousand. So 6,500 rounds to 7,000, not 6,000.

    The idea underneath. A number rounds to a target value T at a given place when it falls in a range from a half-unit below T (included) up to one less than a half-unit above T. For 6,000 to the nearest thousand, that range is 5,500 through 6,499.