Signs

Any numerical answer which is capable of having a plus or minus sign must have the appropriate sign included with the number. Students often miss out the sign, especially a plus sign. Mathematicians often try to argue that the positive sign isn't necessary. This may be true in Maths, but it isn't in Chemistry. There is a good reason for this. The absence of a sign might suggest that it is positive. Alternatively, it may indicate that the sign has been forgotten. Giving the positive sign indicates clearly to another person that you think the number has a positive value. If the number can only take on a positive value then there is no need to include a sign. Missing and incorrect signs frequently cause students to lose marks in exams and assessments.