Reflection: Coherence Combining Like Terms - Section 3: Mini Lesson


It's important to emphasize to students that the sign in front of the variable is part of the coefficient and in turn should be included in the shape. This is important when there are several like terms to combine.  For example, students may think 4x + 6y + 3x - 2y is equivalent to 7x+8y, rather than 7x + 4y.  

When I realized that students were making this mistake we worked through a few more examples together.  I had students come up to the board and identify the like terms using the shapes method.

Additional Problems:

1)     9a + c - 2a + d - 3a + 4d

2)     23x + 5y + 6z - 18x + 61y - 5z

3)     41xy + 8z + 2yx + yz - 6z

  Including the Sign
  Coherence: Including the Sign
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Combining Like Terms

Unit 14: Algebra
Lesson 7 of 16

Objective: SWBAT combine like terms.

Big Idea: How can we use order of operations to simplify expressions?

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5 teachers like this lesson
Math, algebraic expression, Algebra, combining like terms
  45 minutes
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