reckoner
  計算者,清算人,計算手冊
  Reck·on·er n. One who reckons or computes; also, a book of calculations, tables, etc., to assist in reckoning.
     Reckoners without their host must reckon twice.   --Camden.
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  reckoner
       n 1: an expert at calculation (or at operating calculating
            machines) [syn: calculator, figurer, estimator, computer]
       2: a handbook of tables used to facilitate computation [syn: ready
          reckoner]