Setting Out Calculations

When setting out your calculation work it is important that you structure your answers. Marks are given not only for the correct answer but also for a clear communication of your thinking as you tackled the problem.

Here are some simple steps to follow.

  • Read the question carefully and extract the information from it by listing the data given to you on the right hand side of your page. Make a neat column of the figures given and the UNITS!!! (and change them into SI units if necessary - for example, times given in minutes should be changed into seconds there and then!)
  • Think about what is happening in the question and if appropriate sketch a diagram to illustrate it - marking on forces, distances etc.
  • Quote the general equation that you are going to use to solve the problem - saying what the letters/symbols stand for.
  • Substitute the symbols/letters with the data you have at the top of the page to leave you with the unknown.
  • Call this unknown 'x' or something - don't put '?' for it!
  • Manipulate the equation and calculate the unknown - put each line of mathematical reasoning on a separate line - use WORDS to explain what you are doing - do NOT simply put a string of = signs between sets of numbers that are not equal

    For example - some students when changing 5 minutes into seconds write

    5 = 5 x 60 = 300


    5 = 300 ????? No way! Illogical maths!

    it should be written:

    5 mins = 5 x 60 seconds = 300s

  • Consider the number of significant figures that the quastion has been written in and then quote the numerical answer to that number.
  • Consider the unit of your answer carefully and add it to the numerical answer.

It is a good idea to make your final answer stand out clearly by putting it on a separate line and writing ANS after it.

Common ways to lose marks:

  • omitting the general equation
  • omitting units
  • using the wrong case of letter for a unit or a symbol
  • illogical maths

Here is an example of correct layout...