## Topic C. Communicating the Precision of Measured Numbers

This topic includes

Section 1. Reporting measurements

Section 2. Rounding

Section 3. Precision of a number, including the concept of significant digits

Section 4. Identifying the interval of actual values for a rounded number.

### Objectives:

- Practice the usual rules for rounding.
- Round a number to a given precision.
- Determine the implied precision of a rounded number, giving it in words, or by a number, or by underlining the significant digits.
- Understand why we donâ€™t do two sequential rounding operations on a number, but do all rounding in one step.
- Understand that rounding numbers ending in exactly half is sometimes done in a different way.
- On a number line, graph the interval of actual values which are consistent with a rounded value.
- Use interval notation to give the interval of actual values which are consistent with a rounded value.
- Use inequality notation to give the interval of actual values which are consistent with a rounded value.
- For a given rounded number, find the maximum error due to rounding and express it as a percentage of the rounded number.