Math is Figure-Out-Able!

#MathStratChat - May 7, 2025

Pam Harris, Kim Montague

In today’s MathStratChat, Pam and Kim discuss the MathStratChat problem shared on social media on May 7, 2025. 


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 mathers! 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 because we chat about our math strategies. 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 comment on each other's thinking.

 

Kim  00:20

Okay, so this Wednesday, our problem was 25 times three-fifths. How would you like to solve this problem? Pause the podcast. Solve it however you'd like. The problem is 25 times three-fifths. Alright. You want to go or you want me to go?

 

Pam  00:34

I want to go. 

 

Kim  00:35

Okay. 

 

Pam  00:36

Okay, so I'm going to think about that as three-fifths of 25, so I'm going to think about that as one-fifth of 25 which is 5. A fifth of 25 is 5, but I need three of those 1/5s. So, 3 times 5 is 15. 

 

Kim  00:50

I like it. I did pretty much the same thing, but when I saw the three-fifths, I thought about 60%.

 

Pam  00:59

Oh.

 

Kim  00:59

So, I guess it wasn't. I had two things happening in my head. So, when I did 60% of 25.

 

Pam  01:06

Yeah.

 

Kim  01:06

The first thing I thought about was 20% was 5, so times 3 to get 60%, so times 3 for 15. Okay. But then I also, when it was percents, I could have thought about 50% of 25. Which is 12.5. And 10%.

 

Pam  01:23

Wait, wait, wait. Say that... Sorry, I was doing something else while you were talking. What did you? 50? 5-0?

 

Kim  01:29

50% of 20... of 12... 50% of 25.

 

Pam  01:33

Okay.

 

Kim  01:34

Is 12.5.

 

Pam  01:35

Okay. 

 

Kim  01:36

And 10% of 25 is 2.5 (unclear).

 

Pam  01:39

Oh, because you're really thinking 60%, so you're like 50 and 10.

 

Pam Harris  01:42

Mmhm. 

 

Pam  01:43

Okay, can I tell you what I was playing with? Yeah. While you were talking, sorry. 

 

Kim  01:47

That's okay. 

 

Pam  01:48

When you said 60% of 25, I then thought, "Sheesh, you could Double and Halve."

 

Kim  01:55

Oh, nice. Yeah, yeah. Yeah.

 

Pam  01:57

And really you could quadruple quarter. So, if I quarter the 60 to get 15%, and quadruple 25 to get 100, then I get 15% of 100.

 

Kim  02:05

Mmhm.

 

Pam  02:06

Yeah, that was kind of fun.

 

Kim  02:07

Mmhm. 

 

Pam  02:08

Thanks for making me think percents. 

 

Kim  02:10

Well, it's super cool because something somebody says can might have you... 

 

Pam  02:15

Ping something, yeah.

 

Kim  02:15

Ping something else, and take a different strategy. And that's what I love about people commenting on each other's ideas. Often, you'll see some. There's like a whole string of people where one person will do something, somebody will say, "Man, I wish I had thought about that!" And then they'll come back and say, "Well, I was thinking about this right now, and that's why." And so, there's often a string of people commenting on each other. So, we love it when you participate every week. We love it even more when you comment on each other's thinking.

 

Pam  02:41

Fantastic. And we post the problems on Wednesdays around 7:00 pm Central time. When you answer, tag me, and use the hashtag Math StratChat. Then, join us here to hear how we're thinking about the problem. Ya'll, thanks for being part of the Math is Figure-Out-Able movement. Math is Figure-Out-Able!