BODMAS is a helpful acronym meaning brackets, order, division, multiplication, addition and subtraction, ensuring that equation steps are completed in the right order. A mathematical question with multiple operations may give different answers depending on the order in which it is solved.
An example of this is the equation 18 + 5 x 2, which may be interpreted as adding 18 and five then multiplying by two. This interpretation gives a different answer to the same question, so BODMAS exists to clarify when each operation should be performed. Multiplication comes before addition, therefore the equation should be solved by multiplying five and two, and then adding 18 for a total of 28.