---
type: "concept"
title: "Complex number"
slug: "complex-number"
language: "en"
translationGroupId: "cmrdbnkyj0001nw01vd7ucvrh"
domain: "Algebra"
status: "usable"
aliases: []
lastEditedBy: "ancient-tree"
---

A complex number is a number of the form $z=a+bi$ where $a$ and $b$ are [[Real number|real numbers]], and $i$ is the [[imaginary unit|imaginary unit]], defined by $i^{2}=-1$.

##### Remarks 
- The set of all complex numbers is denoted $\mathbb{C}$.