Rounding Numbers Calculator

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Round Numbers
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Rounded Number:
3,266.53

How to Round Numbers and Decimals:

Suppose we wanted to round off 838.274. Depending on which place value we're rounding to, the final result can vary.

  • Round to the nearest hundred (838.274) is 800
  • Round to the nearest ten (838.274) is 840
  • Round to the nearest one (838.274) is 838
  • Round to the nearest tenth (838.274) is 838.3
  • Round to the nearest hundredth (838.274) is 838.27

Basic Rules of Rounding

When we "round to the nearest ________", regardless of what goes in that blank the steps are nearly always the same:

  • Identify which place value we are rounding to. The smaller the place value, the more accurate the final result will be.
  • Look to the next smallest place value, or simply put, the one directly to the right of the place value we're rounding to. For example, if we want to round to the nearest ten, we will look at the ones place.
  • If this next smallest place value is less than five (0, 1, 2, 3, or 4), we leave the digit we want to round to alone. Any digits after that number (including the next smallest place value we just looked at) become zeros, or simply drop if after the decimal point. This is called rounding down
  • If the next smallest place value is greater than or equal to five (5, 6, 7, 8, or 9), we increase the value of the digit we're rounding to by one. Just like before, any remaining digits before the decimal point become zeros, and any that are after the decimal point are dropped. This is called rounding up.

Examples

Round to the Nearest Hundred

3250

  • Identify the hundreds digit: 3250
  • Identify the next smallest place value (the digit to the right of the hundreds place): 3250
  • Is that digit greater than or equal to five? YES - we round UP
  • The hundreds digit is increased by one, to 3. Every digit after it becomes a zero.

3250 rounded to the nearest hundred is 3300

Round to the Nearest Ten

323.5

  • Identify the tens digit: 323.5
  • Identify the next smallest place value (the digit to the right of the tens place): 323.5
  • Is that digit greater than or equal to five? NO - we round DOWN
  • The tens digit stays the same. Every digit after it becomes a zero. Digits after the decimal point are dropped.

323.5 rounded to the nearest ten is 320

499

  • Identify the tens digit: 499
  • Identify the next smallest place value (the digit to the right of the tens place): 499
  • Is that digit greater than or equal to five? YES - we round UP
  • The tens digit increases by one. Since 9+1=10, we carry over the 1 into the hundreds place. Each additional digit becomes a zero.

499 rounded to the nearest ten is 500

Round to the Nearest Tenth

0.74

  • Identify the tenths digit: 0.74
  • Identify the next smallest place value (the digit to the right of the tenths place): 0.74
  • Is that digit greater than or equal to five? NO - we round DOWN
  • The tenths digit stays the same. Since the remaining digits are all after the decimal point, they drop.

0.74 rounded to the nearest tenth is 0.7

Round to the Nearest Hundredth

3.141

  • Identify the hundredth digit: 3.141
  • Identify the next smallest place value (the digit to the right of the hundredths place): 3.141
  • Is that digit greater than or equal to five? NO - we round DOWN
  • The hundredths digit stays the same. Remaining digits after the decimal point are dropped.

3.141 rounded to the nearest hundredth is 3.14

Further Reading

About.com on How to Round Numbers

MathPlayground: How do you Round?

Math.com has several lessons on estimating and rounding

 

 

Cite this content, page or calculator as:

Furey, Edward "Rounding Numbers Calculator" From http://www.CalculatorSoup.com - Online Calculator Resource.