2 + 2 = ?

Many employment cases involve disputes about calculations, often relating to sums of money, but also other issues, such as hours worked or weeks employed.

Normally the dispute is about what calculation needs to be made. For example, the claimant will say that he is entitled to 3% commission on his sales, while the respondent claims he is entitled to 2.4%.

Surprisingly often, however, the dispute comes down to a difference in the result of the calculation. For example, the parties agree that 3% commission is owed and that it is on the invoices to be found from page 70 to 77 in the bundle, but cannot agree a final figure. The claimant claims he is owed £3,544, while the respondent insists it is £2,898. The difference is purely arithmetical and it seems obvious that one party must have got its sums wrong.

In an ideal world, such errors would not occur and, if they did, would soon be resolved amicably. In this, less than ideal world, the question arises, should an advocate cross-examine a witness on his maths?

The authors believe not. While the maths may be a question of fact, it is not one that is likely to be illuminated by careful cross-examination. Instead, the sums should be set out in the submissions and the tribunal can, if necessary, do its own arithmetic to check them.

It should be noted, however that this is not necessary the general view and that the authors are aware of at least one tribunal who took the position that a witness should be taken through his calculations. The most sensible approach is to seek guidance from the tribunal, by saying something like “Sir, there is an issue regarding the calculation of this figures. It comes down to a question of arithmetic. Unless you think it would be helpful for me to take the witness through the sums in detail, I think it can be dealt with in submissions.”

The final point to note is that, in an appropriate case, the tribunal’s own arithmetic can be challenged by way of appeal, see Mears v Lloyd Green & Co. for an example. In most cases, however, a tribunal’s mistaken calculation is more appropriately dealt with by applying for a certification of correction or a review.