Calculate to the nearest .
Step 1: Identify the target place value and (Rule)
Step 2: Apply the rounding rule to the value (Substitution)
Step 3: Provide the final rounded result (Answer)
Calculate to (dp).
Step 1: Identify the target place value and (Rule)
Step 2: Apply the rounding rule to the value (Substitution)
Step 3: Provide the final rounded result (Answer)
Calculate to (s.f.).
Step 1: Identify the target place value and (Rule)
Step 2: Apply the rounding rule to the value (Substitution)
Step 3: Provide the final rounded result (Answer)
Explain the for a mass, , given as correct to the nearest kilogram.
Step 1: Determine the and halve it.
Step 2: Calculate the lower and .
Step 3: Write the interval using .
Students often lose marks for 'premature rounding' by rounding numbers halfway through a calculation; always keep full calculator displays or use the 'ANS' button until the final step.
In multi-step calculation questions where the accuracy is not specified, OCR examiners generally expect the final answer to be rounded to significant figures.
For the upper bound in an error interval, do not write a value slightly less than the limit like ; mark schemes require the exact bound () combined with the strictly less than () symbol.
If a question involves money and does not specify accuracy, always round your final answer to decimal places to represent pounds and pence (e.g., , never ).
When finding significant figures for decimals with leading zeros (e.g., ), remember that the zeros at the start do not count as significant figures.
The "5 or More" Rule
The standard rounding convention where a check digit of or rounds the target digit up, while or leaves it unchanged.
Nearest whole number
Rounding a number to zero decimal places, where the tenths digit (st decimal place) acts as the check digit.
Rounding digit
The digit at the place value position you are rounding to.
Check digit
The digit immediately to the right of the rounding digit that determines whether to round up or down.
Decimal places
The positions of digits to the right of the decimal point.
Placeholder zeros
Zeros added to the end of a rounded whole number to maintain the correct place value and magnitude.
Trailing zeros
Zeros placed at the end of a decimal number to demonstrate a specific level of accuracy.
Significant figure
The digits in a number that contribute to its precision, starting from the first non-zero digit.
Degree of accuracy
The specific unit or place value to which a number has been rounded.
Error interval
The continuous range of possible values a number could have been before it was rounded or truncated.
Limits of accuracy
The specific minimum and maximum values (bounds) defining the start and end of an error interval.
Lower bound
The smallest value that would round up to the given corrected value.
Upper bound
The boundary value that the true number must be strictly less than, as it would round up to the next possible increment.
Truncated
A number shortened by cutting off trailing digits rather than rounding.
Inequality notation
Mathematical symbols (such as and ) used to show a range of values.
Put your knowledge into practice — try past paper questions for Mathematics
The "5 or More" Rule
The standard rounding convention where a check digit of or rounds the target digit up, while or leaves it unchanged.
Nearest whole number
Rounding a number to zero decimal places, where the tenths digit (st decimal place) acts as the check digit.
Rounding digit
The digit at the place value position you are rounding to.
Check digit
The digit immediately to the right of the rounding digit that determines whether to round up or down.
Decimal places
The positions of digits to the right of the decimal point.
Placeholder zeros
Zeros added to the end of a rounded whole number to maintain the correct place value and magnitude.
Trailing zeros
Zeros placed at the end of a decimal number to demonstrate a specific level of accuracy.
Significant figure
The digits in a number that contribute to its precision, starting from the first non-zero digit.
Degree of accuracy
The specific unit or place value to which a number has been rounded.
Error interval
The continuous range of possible values a number could have been before it was rounded or truncated.
Limits of accuracy
The specific minimum and maximum values (bounds) defining the start and end of an error interval.
Lower bound
The smallest value that would round up to the given corrected value.
Upper bound
The boundary value that the true number must be strictly less than, as it would round up to the next possible increment.
Truncated
A number shortened by cutting off trailing digits rather than rounding.
Inequality notation
Mathematical symbols (such as and ) used to show a range of values.