5.4.2 Importance of Proper Math Notation

Writing math correctly is important, especially for two reasons:

  1. If you write your math clearly, then other people can follow your work. If that other person is your instructor, then your chances of a good grade are much better!
  2. You can check your own work much more easily for mistakes.

The three most important things to remember are:

  1. Explain each step in your working clearly.
  2. Lay out your explanation clearly.
  3. Use correct math—make sure that what you write is mathematically correct.

Let’s consider the following scenario.

You want to pave a patio that’s 18 feet long by 9 feet wide, with paving slabs that are two feet square. The paving slabs cost $8 each. How many will you need, and what will they cost in total?

You go to your local contractor who says “Let me see …” and scribbles down the following calculation:

equation sequence 18 multiplication nine solidus two multiplication two equals 40.5 multiplication eight equals 324 call it 44 to be safe, so = 44 multiplication eight equals 352.

Activity symbol Activity: What’s Wrong with the Math?

Can you see the difficulty with his work and can you suggest any improvements?

Hint symbol


Remember that mathematics that has been written well is easy to follow and uses correct notation. List any problems or issues you see. Think about how you have seen math presented in the units so far.

Solution symbol


  • First of all, you’re going to have great difficulty in checking his work. This could be a problem—you really don’t want to buy more slabs than you need! Nor do you want to purchase too few to finish the job.
  • Secondly it’s not clear what the answer is—what does that final figure of 352 represent? Slabs, or dollars?
  • Third, it’s mathematically incorrect at a number of points. That could lead to some serious miscalculations—more or fewer slabs, and over- or under-charging. In particular, the contractor misuses the equal sign a few times. You can only use an equal sign if the expression on the left is equivalent, that is gives the same answer, to the expression on the right. If it’s not, this means you need another, separate step.

5.4.1 Writing Mathematics

5.4.3 Understanding a Solution