Multiplication Imaginary Part Only (Level 1)

This math topic focuses on practicing the multiplication of imaginary numbers, specifically those parts of complex numbers that only have an imaginary component (denoted as 'i'). It explores situations where two imaginary parts are multiplied, requiring learners to simplify their products, which are purely real numbers with negative signs, due to the property \(i^2 = -1\). Each problem presents a pair of imaginary numbers for multiplication, followed by multiple choice answers, emphasizing the correct application of rules governing the arithmetic of complex numbers.

Work on practice problems directly here, or download the printable pdf worksheet to practice offline.

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Complex Numbers - Multiplication Imaginary Part Only Worksheet

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Complex Numbers - Multiplication Imaginary Part Only
1
Multiply these complex numbers and simplify
A LaTex expression showing (-5i) times (5i)
a A LaTex expression showing 26
b A LaTex expression showing 25 - 1i
c A LaTex expression showing 27
d A LaTex expression showing 25 + 1i
e A LaTex expression showing 25
f A LaTex expression showing 25 + 2i
2
Multiply these complex numbers and simplify
A LaTex expression showing (-3i) times (-6i)
a A LaTex expression showing -20
b A LaTex expression showing -19
c A LaTex expression showing -18 + 2i
d A LaTex expression showing -18
e A LaTex expression showing -18 - 2i
f A LaTex expression showing -18 + 1i
3
Multiply these complex numbers and simplify
A LaTex expression showing (-4i) times (4i)
a A LaTex expression showing 15
b A LaTex expression showing -16
c A LaTex expression showing 16
d A LaTex expression showing 16 + 2i
e A LaTex expression showing 14
f A LaTex expression showing 18
4
Multiply these complex numbers and simplify
A LaTex expression showing (5i) times (4i)
a A LaTex expression showing -20
b A LaTex expression showing -20 - 1i
c A LaTex expression showing -21
d A LaTex expression showing -20 + 1i
e A LaTex expression showing -22
f A LaTex expression showing -20 - 2i
5
Multiply these complex numbers and simplify
A LaTex expression showing (4i) times (-4i)
a A LaTex expression showing 17
b A LaTex expression showing 14
c A LaTex expression showing 16 - 2i
d A LaTex expression showing 15
e A LaTex expression showing 16
f A LaTex expression showing 16 - 1i
6
Multiply these complex numbers and simplify
A LaTex expression showing (2i) times (-6i)
a A LaTex expression showing 11
b A LaTex expression showing 12 + 2i
c A LaTex expression showing 12 - 2i
d A LaTex expression showing 12
e A LaTex expression showing 12 - 1i
f A LaTex expression showing 10
7
Multiply these complex numbers and simplify
A LaTex expression showing (2i) times (5i)
a A LaTex expression showing 10
b A LaTex expression showing -10 - 1i
c A LaTex expression showing -10 - 2i
d A LaTex expression showing -9
e A LaTex expression showing -10 + 2i
f A LaTex expression showing -10
8
Multiply these complex numbers and simplify
A LaTex expression showing (2i) times (-4i)
a A LaTex expression showing 8 - 2i
b A LaTex expression showing 8 + 2i
c A LaTex expression showing 8
d A LaTex expression showing 8 + 1i
e A LaTex expression showing 10
f A LaTex expression showing 8 - 1i