Polynomials: Add, Subtract, and Multiply

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Mathematics · Algebra I
SP-ALG1-009 · Free to print and use in your classroom · substituteplans.com
Page 2
Polynomials: Add, Subtract, and Multiply
Mathematics · Algebra I · Grades 9-10 · 50 minutes
Time needed
50 minutes (one class period)
Prep
Copy the 2-page worksheet (one per student). Write the worked examples on the board.
Technology
None. Calculators are optional for arithmetic only.
Student
independence
High. Students work alone, then compare with a partner.
Copies to make
One 2-page worksheet per student
Materials
Pencils, Worksheet, Whiteboard or chalkboard
Goal for today: Students will add, subtract and multiply polynomials by combining like terms and applying the
distributive property.
Before the bell
☐ Copy the worksheet, one per student (2 pages).
☐ Write on the board: Like terms have the same variable and the same exponent. Example: 3x² and 5x² are like
terms; 3x² and 5x are not.
☐ Write two examples. Add: (2x + 3) + (x + 4) = 3x + 7. Subtract: (5x + 2) − (2x − 1) = 5x + 2 − 2x + 1 = 3x
+ 3.
☐ Keep the answer key on your desk. You do not need to solve anything yourself.
Say this to start
Good morning! Today you will work with polynomials, which are expressions made of terms like 3x² + 2x − 5. You will
add them, subtract them, and multiply them. The big ideas are on the board: only combine like terms, distribute the
minus sign when you subtract, and multiply every term by every term. Work on your own, then we will check answers
together.

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Mathematics · Algebra I
SP-ALG1-009 · Free to print and use in your classroom · substituteplans.com
Page 3
Run of show
Minutes
What you do
What students do
0–5
Take attendance the way the school requires. Hand out the
worksheet face down and ask students to wait.
Settle in and take out a pencil.
5–13
Read the board examples aloud. For subtraction stress:
“The minus sign changes the sign of EVERY term in the
second polynomial.” Show multiplying: (x + 2)(x + 3) = x²
+ 3x + 2x + 6 = x² + 5x + 6.
Follow along and copy the examples.
13–22
Tell students to complete Part A (problems 1–4, add and
subtract).
Add and subtract the polynomials,
combining like terms.
22–38
Tell students to complete the area box and problem 5, then
problems 6–11, and Part C (12–13). Walk the room and ask,
“Did you multiply every term by every term?”
Multiply using the area box and the
distributive property.
38–46
Read the answers from the key. Students mark each right
or wrong and fix mistakes.
Check their work and correct errors in a
different color if possible.
46–50
Have students write the exit ticket sentence, then collect
all worksheets and stack them for the teacher.
Write one sentence. Hand in the worksheet.
If things go wrong
• If students make sign errors in subtraction, tell them to rewrite the problem with the minus sign distributed to
every term in the second polynomial.
• If students ask what “simplest form” means, tell them to combine all like terms and write terms from the
highest exponent to the lowest.
• If a student is stuck multiplying binomials, tell them to use the area box or write every product: first, outer,
inner, last.
• If the class is noisy, remind them this is individual practice time. Partners may whisper during the checking
time.
Early finishers
• Multiply (x + 2)(x² + 3x + 1) by multiplying every term and combining like terms.
• Make up two binomials whose product is x² + 6x + 8, then check by multiplying.
Support and challenge
• Support: Have students complete problems 1, 2, 5, 6 and 7, and use the area box for each multiplication.
• Challenge: Ask students to expand (x + 1)(x + 2)(x + 3).

SubstitutePlans.com
Mathematics · Algebra I
SP-ALG1-009 · Free to print and use in your classroom · substituteplans.com
Page 4
Notes for the teacher (you fill this in)
Jot a few lines before you leave. A full Daily Sub Report is in the free Sub Survival Kit at SubstitutePlans.com.
How far the class got / what to pick up next:
Students who were especially helpful:
Anything the teacher should know: