# QEF

## English[edit]

### Etymology[edit]

Latin *quod erat faciendum* (“what was to have been done”), from Ancient Greek *ὅπερ ἔδει ποιῆσαι* (hóper édei poiêsai).

### Initialism[edit]

**QEF**

- “quod erat faciendum”, “what was to have been done” – used to end a mathematical passage other than a proof.

#### Usage notes[edit]

Much less used than *QED*. Traditionally used to end passages other than proofs, such as geometric constructions – a “how-to”, not a persuasive argument.