Corporation tax liability

Hi, I have a general query with respect to calculation of corporation tax liability. When the question asks you to calculate the corporation tax liability for a company but, in order to arrive to the answer you have to calculate the tax adjusted trading profit, would you recommend calculating it all in one proforma as was done in 'Neung Ltd' from December 2010 or would you suggest calculating the tax adjusted trading profit in one proforma and then the corporation tax liability in another? Thanks!