ABSTRACT

Mathematics is used in many different engineering applications but are underpinned through certain conventions, which are not always signposted. For instance, all numbers tend to be positive unless otherwise stated. The number 5 for example is actually positive otherwise it would be shown as −5. In fact, it can also be represented as 5/1 but we tend not to indicate the numerator in normal convention. There are other mathematical conventions used when adding or subtracting numbers. For example:

like signs add: unlike signs subtract

3 + (+7) = 3 + 7 = 10 (positive meets a positive = like signs add) 3 + (−7) = 3 − 7 = −4 (positive meets a negative = unlike signs subtract)

The same applies when multiplying and dividing, like signs show a positive results, unlike signs a negative one. This applies when you multiply two negative numbers.