When writing formulas it is important to have an understanding of the rule of BODMAS. Not understanding this rule could result in incorrect formulas. BODMAS stands for:
In a nutshell, that means that Excel will divide or multiply before it adds or subtracts unless specified by brackets.
For example, the formula =5+3/2, we would expect the result to be 4.
However Excel produces the result 6.5. Why?
Because of BODMAS Excel calculated 3/2 and then that number was added to 5.
To specify that we want Excel to add 5 and 3 and then divide the answer by 2 we enclose it in brackets.
As you can see if you are hoping to use add and subtract along with multiply and divide in a formula, you need to know BODMAS.