Math is Figure-Out-Able!

#MathStratChat - October 2, 2024

Pam Harris, Kim Montague

In today’s MathStratChat, Pam and Kim discuss the MathStratChat problem shared on social media on October 2, 2024. 


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 Harris.

 

Kim  00:07

And I'm Kim Montague.

 

Pam  00:08

And this is a MathStratChat episode where 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, this week, our problem was 19% of 20. How would you solve this problem? Pause the podcast, solve the problem however you'd like, and then come on back to hear how we solve it. Problem is 19% of 20. 

 

Pam  00:34

Awesome. Alright, you okay if I go first? 

 

Kim  00:37

Sure.

 

Pam  00:38

So, I'm thinking about 20% of 20.

 

Kim  00:41

Okay.

 

Pam  00:41

And that would be a bit too much, so then I'll take off 1% of 20. So, I'm actually going to find the 1% of 20 first. If I'm thinking about 10% of 20, that's 2, so 1% of 20 would be 0.2 or two-tenths. 20% of 20. I just found 10% of 20 and said that that was 2, so 20% of 20 would be double that or 4. Yeah. I (unclear) also thinking about just finding 22% of 20 (unclear). So, now 20% of 20 is 4, subtracting 1%, which is 0.2 or two-tenths. And 4 subtract two-tenths, 3 and 8/10 or 3.8. Oh, which is interesting. That 3.8 is now screaming at me with the connection between 19 and 20. But go ahead. 19 and 2 really? 19 and 2. 38.

 

Kim  01:37

Yeah.

 

Pam  01:37

Yeah.

 

Kim  01:38

Yeah. So, I'm going to do something similar but not. I'm going to go 20% of 19.

 

Pam  01:48

Ah. 

 

Kim  01:48

So, it's, you know... Which is really... Sometimes when I say things out loud, I'm like, "Oh, that is a nice connection," even though I've said it to myself 100 times. 19% of 20 and 20% of 19. So, 20% of 19 doesn't really make me super excited to be honest with you, so I'm going to go 20% of 10. 20% of 10. What is that? 2? And 20% of 9... Bear with me. 20% of 1 would be 0.2, so 20% of 9 is going to be 0.2 less than the 2 I just found. Man, I want to be on a ratio table right now. I'm just writing equations. I don't know why. So, 20% of 10 is 2, 20% of 9 is 1.8, so together 20% of 19 is 3.8. Is that what you got?

 

Pam  02:44

Yeah. Not bad.

 

Kim  02:45

Okay. Alright.

 

Pam  02:47

I have to. Sorry. When you said 20% of 19, I thought about finding 10% of 19, which would be 1.9. And then doubling that.

 

Kim  03:00

Yeah, I like that better.

 

Pam  03:03

Yeah. Alright.

 

Kim  03:04

I also thought about 20% of 20, then backing off. Is that what you did? Did you do 20% of 20? 

 

Pam  03:11

No... Yeah, actually. Yes.

 

Kim  03:13

Yeah, but... 

 

Pam  03:15

Oh, isn't that interesting? You can actually use 20% of 20 for both iterations of the problem. 

 

Kim  03:22

(unclear) I was going todo that first, but then I didn't want to. I just wanted to steal your thinking.

 

Pam  03:27

Nice. Alright, ya'll, we can't wait to see what you do each week. Join us on MathStratChat and let us know how you think about the problems and comment on each other's strategies.

 

Kim  03:37

Yeah, these problems are posted every Wednesday at 7:00 pm Central. When you answer, tag Pam and use the hashtag MathStratChat, then join us here to hear what we're thinking about the problem. We love having you as part of the Math is Figure-Out-Able movement.

 

Pam  03:50

Because Math is Figure-Out-Able!