Description: Making general sense of x
times x!
Parent Tape: Early Algebra Ideas
About Binomial Expansion, Stephanie’s
Interview One of Seven
Date: 1995-11-08
Location: Harding Elementary School
Researcher: Professor Carolyn Maher
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Transcriber(s): Aboelnaga, Eman
Verifier(s): Yedman, Madeline!
Date Transcribed: Fall 2010
Page: 1 of 2
Did you ever have anything like this?
[Dr. Maher writes x · x.]
x times x?
We had x plus x. You told me that was two x’s. What
about x times x?
I think I might’ve. I don’t think I’ve done anything like
this this year.
Okay. What do – what do you think that means?
It means x, the variable x, x amount of times.
Okay. That’s that’s interesting. The variable x x amount
of times. Really neat. I’ll buy that.
Um hm.
Okay. Suppose you had numbers.
Okay.
Um ‘cause you said it could be anything. Suppose we
had x and we had x dot x. Right? And if x were two…
It would be two times two.
Two times two. Right?
Um hm.
And if x were three –
Three times three.
Is there another way two times two?
Um, you could write it two plus two?
Okay. And three times three? Does that work the same
way?
No.
Is there a way of writing, you know –
everything the same?
Write everything the same? Right. All the way up to
…if you had four. This is four times four.
Oh! Well, you could use um you could use exponents.
How would you do that?
Well. Two to the second and three to the second.
Okay. So you could – why don’t you write that?
Okay. Like do you want me to make another chart?
Well – well –sure.
Okay.
Description: Making general sense of x
times x!
Parent Tape: Early Algebra Ideas
About Binomial Expansion, Stephanie’s
Interview One of Seven
Date: 1995-11-08
Location: Harding Elementary School
Researcher: Professor Carolyn Maher
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Transcriber(s): Aboelnaga, Eman
Verifier(s): Yedman, Madeline!
Date Transcribed: Fall 2010
Page: 2 of 2
And then tell me how you would write x times x then.
[Stephanie writes.]
How far do you want me to go?
Um until you can give me a writing x times x in general.
Um. x to the x power?
Okay.
Can you do it like that?
Well. Check it out.
Or – x to the second! Oh no! x to the second power?
What do you think? Which do you think it is? x to the x
or x to the second?
x to the second.
Why?
‘cause x to the x power would mean – say x is – x is one
thousand one hundred and fifteen. That would mean one
thousand one hundred and fifteen one thousand one
hundred and fifteen times and that’s –
Pretty big.
Really long.
Okay.
So two x – uh – x to the second.
Okay. Do you know how you read that?
What?
Another way people read the x to the second power?
Sometimes that’s called x-squared.
Oh. Yeah
You knew that. Okay. So is that familiar to you?
Yes.