# Is this a mistake in the VHG Chemistry lectures, or am I an idiot??

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If you are converting cubic inches to cubic cms, and you have this:

1 in cubed x 2.54 x 2.54 x 2.54 = ___ cm cubed

1 1 in 1 in 1 in

do you multiply the 2.54 times itself 3 times, or do you multiply 2.54 x 3???

I don't know if that's gonna print correctly, but I hope yall can figure out what I'm asking.

Ok, it didn't print it right, but the 2.54s are each over 1.

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1 cubic inch = (2.54 cm) ^3 = (2.54 cm)(2.54 cm)(2.54 cm) = 16.4 cubic cm.

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I thought this, but in the lecture she says (mistakenly I believe) that you can just "multiply 2.54x3, which is the same thing." Clearly there is a big difference there. I e-mailed her about it, because it could really mess some kids up with their answers.

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:iagree: If you can get a hold of a MUS Algebra 1 DVD Dr Demme does a great job of teaching this.

ETA never mind. I thought you didn't understand it and didn't realize that she said something different in the video you are watching. You are correct, if she said that she is wrong.

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My guess is that she's just using short hand for saying to do it three times and didn't mean the number 3. You're right though, it should be written differently as it's likely that some may misunderstand.

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She worked the problem out and her answer was very different from ours. She literally multiplied 2.54 times 3. We multiplied it by itself 3 times. Big difference in the answers...

I'm just editing to add that we do LOVE this class, and I'm sure it was just a mistake because she was maybe thinking she'd take a short cut and not really thinking it through. I don't want to make her sound incompetent at ALL - we have thoroughly enjoyed using this, and it is a lifesaver!! I just wanted to be sure that we weren't misunderstanding. I did e-mail her letting her know it was explained in error, so that maybe she can correct it in the voice threads.

Edited by StaceyinLA

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