Definition of sum-of-the-years'-digits method

A method of accelerated depreciation (higher charges are taken at the beginning of a fixed asset's useful life). Give each year of the asset's life a digit (1 for the first year, 2 for the second, etc.) and add the digits together. In the case of five years, the sum will equal 15. In the first year, a charge will be taken equal to 5/15 of the total cost of the asset (minus its salvage value). In the second year, a charge equal to 4/15 will be taken. In the third year, 3/15, etc.