20 questions
9th - 9th Grade
Mathematics
Algebra 2 Complex Numbers is a Grade 9 mathematics worksheet with 20 multiple-choice questions focused on representing and simplifying complex numbers. Students identify the imaginary unit and the standard form a + bi, evaluate square roots of negative numbers, and use i² = -1 while working with complex-number expressions. The questions also ask students to add and subtract complex numbers and multiply binomials containing i, including products and squared expressions. This free printable worksheet gives students repeated practice selecting the correctly simplified real and imaginary parts from plausible answer choices. It includes a complete answer key for checking understanding, reviewing sign errors, and identifying which complex-number operations need further instruction.
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WorksheetsAnswer Key2i
a+bi
13-84i
-24+33i
10+11i
-20-35i
This Grade 9 mathematics worksheet uses 20 multiple-choice questions to practice the imaginary unit, standard form a + bi, square roots of negative numbers, and the rule i² = -1. Students also simplify addition, subtraction, products, and squared complex-number expressions by combining real and imaginary parts and selecting the correct result.
Introduce i² = -1 and standard form a + bi before assigning the questions, then model one addition problem and one binomial product. Have students label the real and imaginary terms as they work, and use the answer choices to discuss why sign errors or an unreduced i² term produce incorrect results.
Students may treat √-4 or √-81 as ordinary negative real roots instead of imaginary values, or forget that i² equals -1 when multiplying terms such as (2i)(3i). In the addition, subtraction, and multiplication items, watch for combining unlike parts, distributing a subtraction incorrectly, and losing negative signs during binomial expansion.
The worksheet is available as a printable PDF and as a digital quiz on Wayground, and it includes a complete answer key. You can grade printable submissions by scanning student work with the Wayground for Teachers app, while the digital quiz can be completed and reviewed online.
In the worksheet’s Advanced Settings, adjust font spacing or choose a larger font size to make the complex-number expressions and multiple-choice options easier to read. You can also enable a dyslexia-friendly font or translate the worksheet into another language while keeping the practice focused on simplifying complex-number expressions.
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