Math is Figure-Out-Able with Pam Harris

#MathStratChat - October 4, 2023

October 04, 2023 Pam Harris
Math is Figure-Out-Able with Pam Harris
#MathStratChat - October 4, 2023
Show Notes Transcript

In today’s MathStratChat, Pam and Kim discuss the MathStratChat problem shared on social media on October 4, 2023. 

Note: It’s more fun if you try to solve the problem, share it on social media, comment on others strategies, before you listen to Pam and Kim’s strategies.

Check out #MathStratChat on your favorite social media site and join in the conversation.

Twitter: @PWHarris

Instagram: Pam Harris_math

Facebook: Pam Harris, author, mathematics education

Want more? Check out the archive of all of our #MathStratChat posts!

Pam  00:00

Hey, fellow mathematicians! Welcome to the podcast where Math is Figure-Out-Able. I'm Pam. 


Kim  00:06

And I'm Kim. 


Pam  00:07

And this episode is a MathStratChat episode. That's where every Wednesday evening, I throw out a math problem on social media, and people from around the world chat about the strategies they use. And we love hearing how people are thinking. Seeing how people are thinking? Reading how people are thinking.


Kim  00:23

(laughs) Reading. Okay, so this Wednesday, our problem was 12 times 75. And we're curious, how would you solve this problem? Pause the podcast. Solve it however you want. The problem is 12 times 75. Solve it, and come back to hear how we solve it.


Pam  00:39

Okay, Kim, I want you to solve this one first today because you do this thing that I'm getting better at, and I'm kind of curious if you're going to do today. I don't know if you are, but I'm kind of curious. So, what are you thinking about? If you don't mind. Do you mind going first? 


Kim  00:52

No, I don't mind.


Pam  00:52

12 times 75.


Kim  00:54

I haven't thought about this problem yet. Okay, 12 times 75. When I see 75, I want to call that 75%. So, I'm going to go 75% of 12.


Pam  01:03



Kim  01:05

Is that what you thought I would do?


Pam  01:06



Kim  01:07

Oh. Oh.


Pam  01:08

That's okay, though.


Kim  01:08

You're going to have to tell me what you thought. So, I'm going to give 75% of 12, which is 9. But that's if it was 75%. So, I'm going to scale up and say 75 times 12 is going to be 900.


Pam  01:25

How do you know? I agree, by the way. How do you know 75% of 12? Do you just know that? Because you think in terms of percents a lot.


Kim  01:32

I do. I do think of. Well, I mean, there's four 3s, so if I need three of the 3s that would be 9.


Pam  01:39

Okay. Yeah. 


Kim  01:41



Pam  01:42

So, kind of like one-fourth is 3, so 3.... Which is kind of maybe.


Kim  01:46

So, it's 3 and 1/4.


Pam  01:47

Yeah. it's kind of maybe where I was going to go. I was going to think about... I guess I was thinking about 75% of 12, but I was going to think about it as 25% of 12, which is 3, and then scale that up times 3. I'm thinking about the other strategy I'm messing with in my head. To get the 9, and then scale up to 900. So, what I thought you were going to do is think about quarters. Because I'll never forget. We have this super cool video of you working with third grade kids. Fourth grade? Fourth grade kids. And this kid said something about 25s and you said, "Sure, wish I knew something about quarters." 


Kim  02:19

You say that a lot.


Pam  02:21

I do because I think it was so... Like, when you said it, I was like, "What do I know? I don't mess with quarters." I didn't as much. "Could you? Could you think about quarters for this problem? I'm kind of curious.


Kim  02:32

I kind of feel like I did when I was thinking 75.


Pam  02:35

Well, but you were thinking about percent. Like I mean like quarters of a dollar. Like quarters in a dollar. The coin, a quarter. No? When you say, "Sure, wish I knew something about quarters," do you actually mean...


Kim  02:46

Like, 12 quarters and 12 quarters and 12 quarters. So, 25 times 12. 25 times 12. 25 times 12. (unclear)


Pam  02:53

Yeah, I think maybe if you thought about 12 quarters.


Kim  02:56



Pam  02:57

And then, you needed 3 of those.


Kim  02:58



Pam  02:59

So, how would you?


Kim  03:00

(unclear) So, I would say 12 quarters is $4.00. 12 quarters isn't $4.00. 12 quarters is $3.00.


Pam  03:08

You did the same thing I did. 


Kim  03:12

12 quarters is $3.00. And that 3 times would be $9.00.


Pam  03:18

It would be $9.00. Or that 900 that we got. Cool. And if we wanted to we could. 12 is a nice number. We could have thought about that as 10 and 2. 


Kim  03:27



Pam  03:27

Times 75. And what is that? Is that 750? Plus two 75s is 150. And 750 plus 150 is 900. So, lots of nice things that we can do with this problem. 


Kim  03:38

Oh, I just thought of something else I would love. 


Pam  03:39

Alright, bring it on. Bring it on.


Kim  03:40

How many strategies do we want?


Pam  03:42

Well, I'm curious. I like hearing how you think.


Kim  03:45

(unclear) Because of the 75 has got a 25 in there, that's really nice to say 12 is 3 times 4, and 75 is 25 times 3. So, if you group the 25 and 4, it's like 9 times 100.


Pam  04:02

Oh, I just heard your pencil. You just totally drew. 


Kim  04:03

Oh, did you? Oh, God. Sorry. 


Pam  04:05

No, no, no. You drew parentheses, huh? I heard you go.


Kim  04:07

I did.


Pam  04:08

You totally. I could totally hear you like put the parentheses. Because I literally wrote down 3 times 4 times 25 times 3.


Kim  04:14

I did too.


Pam  04:14

And then, you wrote down. I heard your Ticonderoga sharp pencil regroup the 4 times 25, and then you end up with 9 times 4 times 9 times 100. Yeah, that's cool. So, a little flexible factoring happening with that problem. That is awesome. And now, we can't wait to see everyone else's math strategy. We wonder if it was like one of ours or something entirely different.


Kim  04:36

Yeah. Represent your thinking, and take a picture of your work or screenshot, and tell the world on social media. While you're there, comment on other people's strategies, would you? People like that.


Pam  04:45

Yeah, it's so fun to see you commenting on everybody else's thinking. Just like Kim and I are commenting on each other's thinking here. And tag me at @PWHarris on that thing with the X. I think it's still Twitter. I don't know. Instagram, PamHarris_math. Facebook, Pam Harris, author mathematics education. Make sure use the hashtag MathStratChat. And then, check out our next MathStratChat problem every Wednesday around 7pm Central Time, and then come back here to hear how we're thinking about problem. We love having you as part of the Math is Figure-Out-Able movement. And thank you for helping us spread the word that Math is Figure-Out-Able!