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Approximate measurements - Intermediate & Higher tier – WJECRounding to decimal places

Approximation includes estimation, rounding to powers of 10, decimal places and significant figures.

Part of MathsNumber

Rounding to decimal places

When rounding using (dp), the degree of accuracy that is required is usually given. However, there are certain calculations where the degree of accuracy may be more obvious. For example, calculations involving money should be given to two decimal places to represent the pence.

To round to a decimal place:

  1. look at the first digit after the decimal point if rounding to one decimal place or the second digit for two decimal places
  2. draw a vertical line to the right of the place value digit that is required
  3. look at the next digit
  4. if it’s 5 or more, increase the previous digit by 1
  5. if it’s 4 or less, keep the previous digit the same
  6. remove any numbers to the right of the line

Examples

Round 248.561 to one and two decimal places.

  • 248.5|61 to one decimal place is 248.6
  • 248.56|1 to two decimal places is 248.56

Notice that your answer should have the same number of decimal places as the approximation asked for.

Round 0.08513 to one and two decimal places.

  • 0.0|8513 to one decimal place is 0.1
  • 0.08|513 to two decimal places is 0.09

Question

Round 249.5046 to one and two decimal places.

Question

Round 0.9583 to one and two decimal places.

Question

Round 598.053 to one and two decimal places.