Add, subtract and multiply complex numbers

Answer Key - Grade 11 Math Worksheet - Challenge Me

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

1. 1.

   Ren simplifies a two-step math club puzzle. What is (2 + i)(3 − 2i) − (1 + 4i)?

   7 − 5i
2. 2.

   Tala's robot multiplies, then slides by -4 + 2i. What is (1 + 3i)(2 − i) + (-4 + 2i)?

   1 + 7i
3. 3.

   Esme finds a hidden pin on a grid map. What is (-2 + 3i)(2 + i) + (6 − 3i)?

   -1 + i
4. 4.

   Kira raises 1 − i to the fourth power on a puzzle card. What is (1 − i)⁴?

   -4
5. 5.

   Luz cubes 2 + i on the board, one factor at a time. What is (2 + i)³?

   2 + 11i
6. 6.

   Milo cubes a pin at 1 + 2i on a grid map. What is (1 + 2i)³?

   -11 − 2i
7. 7.

   Noah's robot is at 4 + i. It is multiplied by i three times, so three quarter turns. What is i³(4 + i)?

   1 − 4i
8. 8.

   Pia's kite sticker at -3 + 2i makes two quarter turns about 0. What is i²(-3 + 2i)?

   3 − 2i
9. 9.

   Ren turns a pin at 2 − 5i three quarter turns about 0. What is i³(2 − 5i)?

   -5 − 2i
10. 10.

    Tala multiplies 1 + 6i by i⁵ for a puzzle, five quarter turns. What is i⁵(1 + 6i)?

    -6 + i