Reckoner

• (n.) One who reckons or computes; also, a book of calculations, tables, etc., to assist in reckoning.
Found on http://thinkexist.com/dictionary/meaning/reckoner/

reckoner

ready reckoner noun a handbook of tables used to facilitate computation
Found on https://www.encyclo.co.uk/local/20974

Reckoner

Reck'on·er (-ẽr) noun One who reckons or computes; also, a book of calculations, tables, etc., to assist in reckoning. « Reckoners without their host must reckon twice.» Camden.
Found on http://www.encyclo.co.uk/webster/R/24

reckoner

[n] - a handbook of tables used to facilitate computation
Found on http://www.webdictionary.co.uk/definition.php?query=reckoner
No exact match found