既き知ち数すうきちすうMeanings1nounknown quantitymathematicsMathematical term for a value that is already known or given, often contrasted with 未知数 (unknown quantity).See also: 未知数この方ほう程てい式しきでは、xは既き知ち数すうとして扱あつかいます。In this equation, x is treated as a known quantity.