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# Unit: Complex numbers

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Possible mastery points

## Complex numbers introduction

Practice
Parts of complex numbersGet 3 of 4 questions to level up!
Classify complex numbersGet 3 of 4 questions to level up!

## The complex plane

Practice
Plot numbers on the complex planeGet 3 of 4 questions to level up!

#### Quiz 1

Level up on the above skills and collect up to 500 Mastery points

## Adding and subtracting complex numbers

Practice
Add & subtract complex numbersGet 3 of 4 questions to level up!

## Multiplying complex numbers

Practice
Multiply complex numbers (basic)Get 3 of 4 questions to level up!
Multiply complex numbersGet 3 of 4 questions to level up!

## Quadratic equations with complex solutions

Practice
Solve quadratic equations: complex solutionsGet 3 of 4 questions to level up!

#### Quiz 2

Level up on the above skills and collect up to 400 Mastery points
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#### Unit test

Level up on all the skills in this unit and collect up to 900 Mastery points!

### About this unit

Complex numbers are built on the idea that we can define the number i (called "the imaginary unit") to be the principal square root of -1, or a solution to the equation x²=-1. From this starting point evolves a rich and exciting world of the number system that encapsulates everything we have known before: integers, rational, and real numbers.