Pam  00:00

Hey, fellow mathers! 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. And, Kim, from the last conference I was just at, I heard a lot of people are actually playing MathStratChat with whoever's in the car with them.

Kim  00:30

Mmm, that's fun.

Pam  00:30

So, the podcast is on. They're driving their kids to school, and they're like, "Hey, let's do MathStratChat!" (unclear).

Kim  00:35

They're like highjacked.

Pam  00:37

Hey, to all of you that are doing that right now, we salute you! Here we go. 

Kim  00:41

Yeah, that's amazing. Okay, so this Wednesday, our math problem was one-fifth minus one-tenth. And we're curious how would you solve this problem? Go ahead and pause the podcast. Solve it however you'd like. The problem is one-fifth minus one-tenth. You want to go first? 

Pam  00:56

Sure, I'll go first. So, I'm thinking about a fifth of $1.00.

Kim  01:00

Mmhm.

Pam  01:01

And a fifth of $1.00 is $0.20. 

Kim  01:04

Mmhm.

Pam  01:05

And so, I've actually written $0.20 down.

Kim  01:07

Mmhm.

Pam  01:07

And then I'm going to subtract a tenth of $1.00 which is $0.10.

Kim  01:12

Mmhm. 

Pam  01:12

So, $0.20 minus $0.10 is $0.10.

Kim  01:16

Mmhm.

Pam  01:17

And I can... If I decide I'm going to go back to fractions, since the problem started in fractions, then I would write that $0.10 as one-tenth. 

Kim  01:25

Hmm.

Pam  01:26

A way to do that. Can I tell you? Unusually, I actually wrote dollar signs today. 

Kim  01:31

Okay.

Pam  01:32

Usually I might... Well, yeah. I might do something like 10 out of 100. Or for one-fifth, 20 out of 100 minus 10 out of 100 even though I'm talking about money. I might be like out of cents. But today (unclear).

Kim  01:43

No decimals? 

Pam  01:45

Well, I mean, I wrote dollar signs with decimals. 

Kim  01:47

Ah, okay, okay. 

Pam  01:48

Yeah, yeah.

Kim  01:49

You just labeled it. That's excellent. 

Pam  01:50

Yeah. I don't usually do that. I don't know why I did today. Alright, what are you thinking?

Kim  01:55

Well, I was just thinking about how I know that half of a fifth is a tenth, and so if you get rid of half of it, then you're left with the same amount. So, it's a tenth.

Pam  02:06

Huh. So, one-fifth minus a half of itself...

Kim  02:10

Mmhm.

Pam  02:10

...would leave you with that another half, or leave you with a half. And since the half is a tenth, and you're left with a tenth? Is that what you're saying.

Kim  02:17

Yep.

Pam  02:18

Ah, nice. I was kind of... If you don't mind, I was anticipating you were gonna do percents, percent girl. 

Kim  02:24

I do like to do percents, but it would sound similar to what you just said. So, a fifth... You said a fifth of $1.00. So, a fifth of 100% is 20%. And so, a tenth would be 10%, so 20% minus 10% is 10%.

Pam  02:41

And if you were doing that, like would you record like a percent symbol kind of like I recorded a dollar sign? 

Kim  02:46

I would have written 20% minus 10% on my paper.

Pam  02:51

Alright. It's your turn. 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. Comment on each other's strategies.

Kim  03:05

Pam posts the problems on Wednesday at 7:00 pm Central, and when you answer, tag her and use the hashtag MathStratChat. Then you can join us here to hear how we're thinking about the problem.

Pam  03:16

We love having you as part of the Math is Figure-Out-Able movement, because Math is Figure-Out-Able!