“定率递减法”是以每期期初固定资产净值,作为计算折旧的基数(不以原值为基数),以一定的比率(期期相同的比率)计算折旧额。这样算出的折旧额,开始较多,以后逐期递减,到使用期末,帐面净值恰好是残余价值。其折旧率是由下列公式计算而得: The “declining rate reduction method” is calculated based on the net fixed assets at the beginning of each period as the base for calculating depreciation (not based on the original value), and calculates the depreciation amount at a certain ratio (the same rate as the period). The amount of depreciation thus calculated starts at the beginning and then gradually declines from period to period. By the end of the use period, the net book value is exactly the residual value. Its depreciation rate is calculated by the following formula: