Fortunately, the answer made no sense in the context of the problem and so I looked over the calculation and found my error. I understand that one of the first things pharmacists are trained to do is to double-check everything, in fact if one observes them dispensing at the chemists it is an automatic action.
Human beings will make mistakes in arithmetic, particularly in a busy, distracting environment.
The question which must be asked as a consequence of the patient drug safety survey must be "how can nurses be trained to evaluate and check all drug doses and how can they be found the time to do this?" and not "what is wrong with maths teaching?"
D Rogerson 41 Checkstone Avenue Bessacarr Doncaster, South Yorkshire