A-level Computing/AQA/Problem Solving, Programming, Operating Systems, Databases and Networking/Real Numbers

Describe the format of floating point numbers, including the concept of mantissa and exponent and the need for normalisation.

Only Two’s Complement representation of mantissa and exponent needs to be covered (IEEE standard does not need to be covered).

Minifloat representations are not expected to be recalled.


 * /Floating point numbers/
 * /Normalisation/

Explain the limitations of representing real numbers in a computer system, and how errors occur.


 * Significant digits
 * Precision
 * Rounding errors (absolute errors, relative errors)
 * Cancellation Error
 * Underflow
 * Overflow


 * /Errors/