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Let’s help Lisa out in the comments, mmk?

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## Converting decimals to fractions

What do you see as the issue here?

(Thanks Andy for sending these in!)

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## Constants and Exponents

(Thanks to Pam for the submission.)

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## Cross addition isn’t a thing

Presented without comment, and with thanks to Andrew.

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## Rational Expressions

How would you help this student?

Another thought: would this student have made this mistake at the beginning of the problem? In other words, is this mistake more likely to happen as the problem goes on than at the beginning? If so, then what does that say about problem-solving?

Thanks to Anna for the submission!

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## A Parallelogram is a Rhombus

These are some “Always, Sometimes, Never” questions. Like, “Is it always, sometimes or never true that a rhombus is a parallelogram.”

What’s the fastest way to help these students?

(Thanks for the submission, Tina C!)

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## Factoring + Rational Expressions

What’s the fastest way of helping these students?

Thanks to Anna for the submissions.

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## Multiplication and Exponents

Dip into the archive and check out our other exponent mistakes. What do you notice?

Thanks to Julie for the submission!

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## PEMDAS and powers

Question: Evaluate the expression $-z^{2} + x(3-y)^2$  when $x = 10$,   \$latex y = -2\$, and  \$latex z = -2\$.

What happened?  First, I HATE PEMDAS AND ANYONE WHO USES IT.  This starts early, and students are already brainwashed by 6th grade when I get them.  All of the GEMS in the world can’t seem to fix this.  I hate PEMDAS because students see parenthesis and go into “I must do that first” mode, even when there is only ONE number inside the parenthesis.  Just because it is in parenthesis, one number, for example (2), does NOT a group make.

Discuss her evaluation of the problem, and her next steps, either in the comments or at her place.

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## Trig Identities are just really hard to prove

What’s going on here? Tell a story of how this kid wrote this stuff?

Thanks to Jonathan Newman for the submission!