0580

Using a Calculator

Number

The display is not always the answer

  • A displayed figure has to be interpreted in the context the question set
A scientific calculator with a value of −2 in its display, above the function keys and the number pad with its DEL and AC keys
Source: Using a calculator by Save My Exams
  • In money, a display of 7.5 means £7.50, because currency is written to two decimal places
  • In time, a display of 1.75 means 1 hour 45 minutes, because 0.75 of an hour is 45 minutes
  • Reading 1.75 as "1 hour 75 minutes" is the error this warns against
  • A display in standard form, shown with a small exponent, must be written out properly rather than copied with the calculator's own notation
Exam tip

"Show that" appears in 21 of the 43 papers, and it means the answer is already printed: the marks are entirely for the working. Show a value more accurate than the one you are asked to show, then round to it, because working that only reproduces the printed figure has not shown anything.