this is a little tricker than I'm used to for a skill testing question. Please help.
This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, see the FAQ.
The order in which you do the calculations can be remembered using "BODMAS"
Always do arithmetic in the following order:
It's explained well here:
So for your example: 25+80-5/2*4
First divide 5 by 2, then multiply that by 4. Add 25 to 80 then take the result of the previous multiplication from this addition.