Add, subtract and multiply complex numbers

Answer Key - Grade 11 Math Worksheet - Building Confidence

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

1. 1.

   Luz's robot is at 3 + 2i and slides by 5 − 4i on the complex plane. What is (3 + 2i) + (5 − 4i)?

   8 − 2i
2. 2.

   Noah's kite is drawn at 4 − 9i and is moved by -1 + 5i. What is (4 − 9i) + (-1 + 5i)?

   3 − 4i
3. 3.

   Pia adds two puzzle numbers on the board. What is (-2 − 3i) + (9 + 6i)?

   7 + 3i
4. 4.

   Ren's robot moves from 7 + 3i back by 2 − 5i. What is (7 + 3i) − (2 − 5i)?

   5 + 8i
5. 5.

   Tala subtracts on a puzzle card. What is (4 − 6i) − (9 + 2i)?

   -5 − 8i
6. 6.

   Zee finds the gap between two pins on a grid map. What is (-3 + 8i) − (-6 + 3i)?

   3 + 5i
7. 7.

   Esme writes a subtraction. What is (10 + i) − (4 − 7i)?

   6 + 8i
8. 8.

   Jun's robot at 3 + 5i is multiplied by i, a quarter turn about 0. What is i(3 + 5i)?

   -5 + 3i
9. 9.

   Kira turns the pin at 4 − 5i by multiplying by i. What is i(4 − 5i)?

   5 + 4i
10. 10.

    Milo turns -2 − 7i a quarter turn about 0 by multiplying by i. What is i(-2 − 7i)?

    7 − 2i