Measures and accuracy
Groups
Units and conversion
Converting metric, imperial, squared and cubed units, money and currency.
Time and timetables
Units of time, the two clock notations, durations and timetables.
Rates and reading a measurement
Converting rates, reading scales, and estimating everyday measures.
Rounding and truncation
The ways a number is cut short, and the contexts that override the digits.
Estimation and checking
How much accuracy an answer should carry, and checking it with an estimate.
Error intervals
A rounded, truncated or measured value stands for a range of possible values.
Calculating with bounds
Higher tier: choosing bounds in a calculation and quoting supported accuracy.