Q.E.D. is an initialism of the Latin phrase quod erat demonstrandum, originating from the Greek analogous hóper édei deîxai, meaning "which had to be demonstrated". The phrase is traditionally placed in its abbreviated form at the end of a mathematical proof or philosophical argument when what was specified in the enunciation — and in the setting-out—has been exactly restated as the conclusion of the demonstration. The abbreviation thus signals the completion of the proof. An example of Q.E.D. signifying the successful completion of a geometry proof is available in Chapter 2 of the Wikibooks Geometry text.
The numerical value of q.e.d. in Chaldean Numerology is: 1
The numerical value of q.e.d. in Pythagorean Numerology is: 8