The way the formula is written is a bit confusing and can have several interpretations. You need to place brackets in the appropriate locations so the operations can be clearly identified.

Also it would help if you can tells what is this formula is for

Ok in that case we will use the conventional order of operations, or precedence that is referred to as 'PEMDAS' which is in this order

1- inside parentheses or brackets 2- exponents and roots 3- multiplication and division as they appear left to right 4- addition and subtraction as they appear left to right

yeah i know all that mate but still finding it hard to use that to help me. its quite a long equation and lots of brackets to consider. cant u just show me how u would write it with brackets and everything. that would be more helpful. i know all about bodmas but still confused as to how this formula is written on excel

That file should open on any mac that has any version of Excel. Anyway here is another version of that file uploaded to a different site, just in case..