算清 is a resultative verb compound (verb 算 'calculate' + complement 清 'clear'). It means to calculate until the result is clear — settling an account, figuring out an exact number, or getting a clear picture of a ratio. Like many resultative compounds, it can be split with 得/不 to form the potential complement: 算得清 ('can figure out') and 算不清 ('cannot figure out'). It can also take 了 for completed action: 算清了 ('have settled').