Add, subtract and multiply complex numbers

Answer Key - Grade 11 Math Worksheet

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

1. 1.

   Noah's robot multiplies two points on the complex plane. What is (2 + 3i)(4 − i)?

   11 + 10i
2. 2.

   Pia multiplies on a math club card. What is (1 − 2i)(3 + 5i)?

   13 − i
3. 3.

   Ren works out a product on the board. What is (-3 + i)(2 + 4i)?

   -10 − 10i
4. 4.

   Tala multiplies two pins on a grid map. What is (5 + 2i)(1 + 3i)?

   -1 + 17i
5. 5.

   Zee squares 3 + 2i to find where a kite sticker lands. What is (3 + 2i)²?

   5 + 12i
6. 6.

   Jun's robot squares its spot, 1 + 5i. What is (1 + 5i)²?

   -24 + 10i
7. 7.

   Kira squares -2 + 3i on the class board. What is (-2 + 3i)²?

   -5 − 12i
8. 8.

   Milo's robot at 5 + 3i is multiplied by -2i: it turns and stretches. What is -2i(5 + 3i)?

   6 − 10i
9. 9.

   Noah multiplies a grid map pin, -1 + 6i, by 4i. What is 4i(-1 + 6i)?

   -24 − 4i
10. 10.

    Pia works out -5i(2 − i). What is -5i(2 − i)?

    -5 − 10i