in estimating yeild sums such complex calculation are very difficult to do on Excel can we just do it on a paper and write the ans on spreadsheet and find required yeild? or Or would mark be deducted for not showing how the yeild was calculated?
Assuming that you are not taking the exam remotely, then you can use paper for workings.
However it is better to do it in the spreadsheet because it is your workings that get the marks, even if you make a mistake somewhere and so end up with a different final answer. You don’t get any marks for workings on paper because it is not collected in.