Grade 11 · Math · Algebra 2

11th grade Add, subtract and multiply complex numbers worksheet

6 printable versionsChallenge Me10 questions · answer keyFree · no account

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Add, subtract and multiply complex numbers

Grade 11 Math Worksheet - Challenge Me

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Circle the best answer, or write your answer on the line.

Tala's robot multiplies, then slides by -4 + 2i. What is (1 + 3i)(2 − i) + (-4 + 2i)?
Zee works a long one on the board. What is (4 − i)(1 + 2i) − (3 − 5i)?
Esme finds a hidden pin on a grid map. What is (-2 + 3i)(2 + i) + (6 − 3i)?
Jun's robot starts at 1 + i and is cubed, turning and stretching. What is (1 + i)³?
Luz cubes 2 + i on the board, one factor at a time. What is (2 + i)³?
Milo cubes a pin at 1 + 2i on a grid map. What is (1 + 2i)³?
Noah's robot is at 4 + i. It is multiplied by i three times, so three quarter turns. What is i³(4 + i)?
Pia's kite sticker at -3 + 2i makes two quarter turns about 0. What is i²(-3 + 2i)?
Ren turns a pin at 2 − 5i three quarter turns about 0. What is i³(2 − 5i)?
Tala multiplies 1 + 6i by i⁵ for a puzzle, five quarter turns. What is i⁵(1 + 6i)?

Add, subtract and multiply complex numbers. Every version has 10 questions, and the answer key prints on the second page.

I can add and subtract complex numbers by sliding: real with real, i with i.
I can multiply two complex numbers with four parts and turn i² into -1.
I can say what multiplying by i does to a point: a quarter turn counterclockwise.

Standard: N-CN.A.2

real part: The across number a in a + bi.

imaginary part: The up number b in a + bi.

slide: Adding a complex number moves a point across and up.

area model: A rectangle cut into four parts, one for each pair of terms.

i²: i × i, which equals -1.

Your child added the real numbers and the i numbers together as one (3 + 2i + 5 − 4i written as 6i).

Your child added the parts but dropped a minus sign.

Your child subtracted only the first part of the second number.

Ask: which numbers go across, and which go up?

Ask: which parts of these numbers are negative?

Ask: what does the minus in front of the brackets do to the i part?

What is the most common mistake with add, subtract and multiply complex numbers?

Your child added the real numbers and the i numbers together as one (3 + 2i + 5 − 4i written as 6i).

How can I help my child with add, subtract and multiply complex numbers?

Ask: which numbers go across, and which go up?

Are these 11th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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