Radicals The Real Number System

Simplifying Radicals


Cool mistake!

A meta-question: what can we learn from a mistake like this, compared to a set of classwork on simplifying this expression?

Linear, Quadratic, and Exponential Models* Quadratic Functions Quadratic Functions Quadratics Radicals

Completing the Square, II

matt owen


Matt submits the above, and Matt writes, “I think it’s especially interesting that this student left the mistake on the board even though she had found the correct solutions by graphing in Desmos.  I’m not really sure if she did half of forty, or sqrt 4 and then stuck a zero on it (she wasn’t sure either).”

I vote for “half of 40.” You?

Radicals The Real Number System


photo (6)


What’s the fastest way that you could help this student?

Yo, thanks KFouss!


N-RN.2 Radicals

A classic: Subtracting radicals

This mistake is a classic in my classroom. What does the student understand about combining like terms, but what is the conceptual model that makes this sort of mistake so enticing?

Radicals Radicals

Adding Radicals


Today’s mistake is a classic, at least in my classroom.  What makes this mistake so tempting for students, and how do you help them see the light?