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U.6 Round decimals

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What does it mean to round decimals?

Rounding decimals means finding a number that is close to the original number, but easier to work with. It helps estimate or simplify numbers in calculations.

Example:
  • 3.76 rounded to the nearest tenth is 3.8
  • 5.432 rounded to the nearest hundredth is 5.43
Note

When rounding, you do not change the value much — you only make it simpler to use in everyday math or estimation.

How to round decimals

To round a decimal, look at the digit to the right of the place value you are rounding to. Then decide whether to round up or keep the same number.

Steps:
  • Find the place you are rounding to (tenths, hundredths, thousandths, etc.).
  • Look at the next digit to the right.
  • If the digit is 5 or greater, round up.
  • If the digit is less than 5, keep the digit the same and drop the rest.
Note

Remember: 5 or more, round up; 4 or less, stay the same. This rule works for any place value.

Rounding to different place values

You can round a decimal to the nearest whole number, tenth, hundredth, or thousandth. The place value you choose depends on how exact you need your answer to be.

Examples:
  • 6.48 rounded to the nearest whole number → 6
  • 4.36 rounded to the nearest tenth → 4.4
  • 9.274 rounded to the nearest hundredth → 9.27
  • 2.4689 rounded to the nearest thousandth → 2.469
Note

Always identify which digit you are rounding to before deciding what happens to the rest of the number.

Rounding decimals in real life

Rounding is useful in everyday situations when exact numbers are not needed, such as dealing with money, measurements, or estimating totals.

Examples:
  • If something costs $12.97, you can round it to $13 when estimating your total.
  • A distance of 5.82 miles can be rounded to 6 miles to make it easier to understand.
  • A weight of 2.46 kilograms can be rounded to 2.5 kilograms for quick comparison.
Note

Rounding helps you make reasonable estimates quickly. It’s a good habit when you want to check if your answers make sense.

Checking your rounding

After rounding, compare your rounded number with the original number to see if it makes sense. The rounded number should be close but simpler.

Examples:
  • Original: 7.62 → Rounded to nearest tenth: 7.6 (close and reasonable)
  • Original: 12.49 → Rounded to nearest whole number: 12 (fits the rule)
Note

If your rounded number is not close to the original, you may have rounded to the wrong place value or made an error in the rounding rule.