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Complex number operations review

Review complex number addition, subtraction, and multiplication.
Want to learn more about complex number operations? Check out these videos:

Practice set 1: Adding and subtracting complex numbers

Example 1: Adding complex numbers

When adding complex numbers, we simply add the real parts and add the imaginary parts. For example:

Example 2: Subtracting complex numbers

When subtracting complex numbers, we simply subtract the real parts and subtract the imaginary parts. For example:
Problem 1.1

Express your answer in the form (a+bi).

Want to try more problems like this? Check out this exercise.

Practice set 2: Multiplying complex numbers

When multiplying complex numbers, we perform a multiplication similar to how we expand the parentheses in binomial products:
Unlike regular binomial multiplication, with complex numbers we also consider the fact that i2=1.

Example 1


Example 2


Example 3

Problem 2.1

Your answer should be a complex number in the form a+bi where a and b are real numbers.

Want to try more problems like this? Check out this basic exercise and this advanced exercise.