Rounding to decimal places

When rounding using decimal places (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 one
  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 1 decimal place, then 2 decimal places.

  • 248.5|61 to 1 decimal place is 248.6
  • 248.56|1 to 2 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 1 and 2 decimal places.

  • 0.0|8513 to 1 decimal place is 0.1
  • 0.08|513 to 2 decimal places is 0.09
Question

Round 249.5046 to 1, then 2 decimal places.

  • 249.5|046 to 1 decimal place is 249.5
  • 249.50|46 to 2 decimal places is 249.50

Notice that 249.50 = 249.5. However, as the question asked for 2 decimal places both numbers are left.

Question

Round 0.9583 to 1 decimal place, then 2 decimal places.

  • 0.9|583 to 1 decimal place is 1.0
  • 0.95|83 to 2 decimal places is 0.96
Question

Round 598.053 to 1 decimal place, then 2 decimal places.

  • 598.0|53 to 1 decimal place is 598.1
  • 598.05|3 to 2 decimal places is 598.05