Pass Check: Rounding & Estimation
Round to decimal places, significant figures, and estimate by rounding to 1 s.f.
Decimal place (d.p.)
A digit's position after the decimal point, counted from the point rightwards.
Significant figure (s.f.)
A digit that contributes to a number's precision, starting from the first non-zero digit.
Estimate
An approximate answer found by rounding each value, usually to 1 significant figure, before calculating.
Truncation
Cutting off digits without rounding; not the same as rounding and rarely tested but examiners flag it as an error.
Quick check
Mixed quiz
1. Estimate the value of 4.8 x 19.6 by rounding each number to 1 significant figure.
2. Estimate the value of 5.2 x 18.8 by rounding each number to 1 significant figure.
3. Estimate the value of 5.0 x 19.2 by rounding each number to 1 significant figure.
4. Estimate the value of 5.1 x 19.0 by rounding each number to 1 significant figure.
5. Round 3.4677 to 2 decimal places.
6. Round 3.4787 to 2 decimal places.
7. Round 3.5227 to 2 decimal places.
8. Round 3.5117 to 2 decimal places.