Subtracting Rational Expressions with Like Denominators

Objectives:

• Students will review subtracting rational numbers.

• Students will review the difference between different polynomials.

• Students will learn how to subtract monomials with common denominators.

• Students will learn how to subtract binomials with common denominators.

• Students will practice all of these skills in their independent work.

Suggested Grades:

Seventh Grade - Eighth Grade - Ninth Grade - Tenth Grade - including special education students

Lesson Procedure:

Print the classroom lesson plan and worksheet questions (see below).

Lesson Excerpt:

- "Now we can begin subtracting rational expressions. Again, if the denominators are alike, then all we need to do is to subtract the numerators. Let's look at an example to start."
- On Board: 4y - 1y
x+ 3 x + 3

- "Now in looking at this problem, the numerators are monomials, and the denominators are binomials. Because the binomials are alike, we only need to subtract the numerators. Let's rewrite the problem to show the common denominator."
- On Board: 4y - 1y
x + 3

- "Once we have rewritten the problem to show the common denominator and that we are subtracting the numerators, we can go ahead and subtract the numerators. In this case, 4y - 1y = 3y. Here is our final answer:"

Continued...