Grade 11 · Math · Algebra 2

11th grade Add, subtract and multiply complex numbers worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

Level: Building Confidence · On Level · Challenge Me

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Add, subtract and multiply complex numbers

Grade 11 Math Worksheet - Building Confidence

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Luz's robot is at 3 + 2i and slides by 5 − 4i on the complex plane. What is (3 + 2i) + (5 − 4i)?
Milo slides a sticker from -6 + 7i by 2 + 3i on a grid map. What is (-6 + 7i) + (2 + 3i)?
Noah's kite is drawn at 4 − 9i and is moved by -1 + 5i. What is (4 − 9i) + (-1 + 5i)?
Pia adds two puzzle numbers on the board. What is (-2 − 3i) + (9 + 6i)?
Ren's robot moves from 7 + 3i back by 2 − 5i. What is (7 + 3i) − (2 − 5i)?
Esme writes a subtraction. What is (10 + i) − (4 − 7i)?
Jun's robot at 3 + 5i is multiplied by i, a quarter turn about 0. What is i(3 + 5i)?
Kira turns the pin at 4 − 5i by multiplying by i. What is i(4 − 5i)?
Luz multiplies -6 + i by i on a puzzle card. What is i(-6 + i)?
Milo turns -2 − 7i a quarter turn about 0 by multiplying by i. What is i(-2 − 7i)?

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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