In proceeding to make a valuation of a class of policies effecting whole-life assurances, the first step is to collect and arrange the amounts of sums assured, inclusive of bonuses, and the corresponding annual premiums under the present ages of the lives assured: that is, under the ages brought up to the date of the proposed valuation. The whole of the data for the class of policies under consideration is thus condensed, and finally exhibited, in a list showing the several amounts for every separate year of present age. The subsequent valuation of these numbers by the proper factors, so as to obtain the respective present values and thence the totals of the present values, involves necessarily a certain amount of calculation, the accuracy of which it becomes very desirable to check; more especially if the figures are considerable and there are many of such computations to make.