Place value and rounding

Round to a number of significant figures or decimal places. Foundation and Higher.

Rounding to decimal places (1 dp, 2 dp ...) cuts off after a chosen point. Significant figures count from the first non-zero digit. Both round half up by convention.

Worked examples

3.4567 to 2 dp = 3.46.

0.004523 to 2 sf = 0.0045. Leading zeros don't count.

123,456 to 3 sf = 123,000. Replace remaining digits with zeros.

Frequently asked questions

3 sf or 3 dp?

Different rules. 0.0042 to 2 sf is 0.0042; to 2 dp is 0.00.

Estimation in GCSE?

Round all values to 1 sf, calculate, check the answer order of magnitude. AQA and Edexcel both test this regularly.