 Its essence is the calculation of the simple multiplications separately, with all addition being left to the final gathering-up stage.The grid method can in principle be applied to factors of any size, although the number of sub-products becomes cumbersome as the number of digits increases.Nevertheless, it is seen as a usefully explicit method to introduce the idea of multiple-digit multiplications; and, in an age when most multiplication calculations are done using a calculator or a spreadsheet, it may in practice be the only multiplication algorithm that some students will ever need.