AlgebraByExample gives students practice solving problems and practice modeling, analyzing, critiquing and articulating mathematical arguments. Each assignment contains several pairs of problems...

Then a “Your Turn” item where students have a chance to practice on their own.

First, a worked example with accompanying analysis question.

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Alta tried to subtract these polynomials but didn’t do it correctly. Here is her work:

In the step marked with an arrow, Alta did not change the signs correctly. Which term does not have the correct sign attached to it?

Your Turn:

Alta tried to subtract these polynomials but didn’t do it correctly. Here is her work:

Your Turn:

Monica simplified this expression correctly. Here is what she wrote:

Why didn’t Monica combine –2x and 20x^{2} ?

Your Turn:

Monica simplified this expression correctly. Here is what she wrote:

Why didn’t Monica combine –2x and 20x^{2} ?

Your Turn:

Helaina tried to simplify this expression, but she didn’t do it correctly. Here is her first step:

What did Helaina do wrong in her first step?

Would it have been okay to write 5 + 2 – 4x? Explain why or why not.

Your Turn:

Helaina tried to simplify this expression, but she didn’t do it correctly. Here is her first step:

What did Helaina do wrong in her first step?

Would it have been okay to write 5 + 2 – 4x? Explain why or why not.

Your Turn:

Tyrone solved this problem correctly. Here is his work:

Why did Tyrone subtract 6 from both sides of the equation?

Why did Tyrone divide by –1?

Your Turn:

Tyrone solved this problem correctly. Here is his work:

Why did Tyrone subtract 6 from both sides of the equation?

Why did Tyrone divide by –1?

Your Turn:

Development of AlgebraByExample was led by Julie Booth (Temple University) through a SERP collaboration with the Minority Student Achievement Network (MSAN). The SERP-MSAN partnership has been supported to conduct this work by The Goldman Sachs Foundation and by the Institute of Education Sciences, U.S. Department of Education, through Grant R305A100150 to Strategic Education Research Partnership Institute. The information provided does not represent views of the funders.

The AlgebraByExample Team

AlgebraByExample by SERP is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.