Hey, fellow mathematicians! Welcome to the podcast where Math is Figure-Out-Able! I'm Pam.
And I'm Kim.
And this episode is a MathStratChat episode. What is MathStratChat? Well, every Wednesday evening, I throw out a math problem on social media and people from around the world chat about the strategies they use. We love seeing everyone's thinking.
So, this Wednesday, our math problem was eleven-twelfths minus two-thirds. How will you solve this problem? Pause the podcast, solve it any way you want. The problem is eleven-twelfths minus two-thirds. Solve it, and then come back to hear how we solve it.
Alright, Kim, you're up first today. How did you solve eleven-twelfths minus two... No. Yeah, two-thirds.
Yeah, so eleven-twelfths just screams a clock to me. And I know I've kind of used that strategy for a couple of weeks now, but it's just what comes naturally. So, if I'm thinking about twelve-twelfths, that's the whole clock. It's all 60 minutes.
Mmhmm.
So, then, eleven-twelfths would just be back 5 minutes, so that's 55 minutes.
Mmhmm.
There's the Over that I like to do. And then, two-thirds I know is 40 minutes. So, it's just 50 minutes. So 55 minutes minus 40 minutes is 15 minutes, which is equivalent to 3 out of 12, which is one-fourth.
And when you said 50 minutes is equivalent to 3 out of 12.
Wait, wait, wait. 15. 15 minutes.
What did I? Whatever I said.
Yeah.
That's what I meant. That's what I meant.
Okay.
When you said 15 minutes is equivalent to 3 out of 12, how did you know that?
Because if I'm thinking about a 3 on a clock, and then a hand being on 3 on a clock, then that is 15 minutes out of the 60 minutes.
Gotcha. So, you didn't actually write down 15 fraction bar 60.
No.
And then, equivalent to 3/12. So, you said 15 minutes. I know where that is. It's on those 3 out of 12.
Yep.
Cool. And then, I'm a little curious. When you saw a 3 out of the 12, did you say to yourself, "Oh, that's a quarter of an hour."
Yes. Well, I thought about the three 5 minute chunks, and so I just know 15 minutes is a quarter of an hour.
Yep. Yep. Cool.
Yep. Would did you do?
Okay, I thought about the eleven-twelfths similar to you, but I... Kind of. I didn't really back up 5 minutes from the hour. I thought about the 11 on a clock. So, I just pictured the minute hand on the 11, and then I thought about two-thirds of an hour as the peace sign. I kind of think about that as like cutting the... I just realized I'm jiggling my pen, and sometimes it makes loud noises, and our editor was telling me the other day, "Don't jiggle
your pen. Sorry, editor." So, I thought about that two-thirds of an hour as being on the 8. Yeah, the minute hand was on the 8. So, if I've got the minute hand on the 8, that's like 8 out of 12. So, then, I thought eleven-twelfths subtract eight-twelfths. And I literally pictured the minute hand on the 8, and the minute hand on the 11, and I thought there's three 5 minute chunks in between those.
Nice.
In other words, it's almost like an elapsed time thing. If I knew that I was at the 40 minutes, or at that 8, then you know the hand was on the 40 minute. And I knew that I had to be somewhere by five till, that's like the 11. Does that make sense?
Mmhmm.
So, to get from 40 minutes to 55 minutes, I've got 15 minutes. "Ooh, I got a quarter of an hour to get there."
Yeah.
So, I kind of thought about the difference between them.
Yes. Oh, that's so nice because we did a subtraction problem last week? The week before? I don't know. But we both removed, and I removed again this time (unclear)
Yeah.
(unclear) the distance between them. (unclear).
Yeah, I was kind of thinking about like getting from... Yeah, I often think about elapsed time that way we're like, "Oh, I have to be there 5 minutes, you know, before the thing starts, so that I'm not walking in late," or whatever. So, then, "How much time do I have? Travel time? Okay. When do I need to leave?" You know like, sort of...
Yeah.
...difference between those two times.
Very cool.
Nice.
Awesome. Very good. Alright, so we can't wait to see your strategy. I wonder if you were like Pam and maybe even found the distance between your subtraction problem, or like mine and you removed in some way, or something entirely different. Represent your thinking, take a picture of your work or screenshot your phone, and tell the world on social media. And while you're there, check out what other people did and comment on their thinking.
Yeah, because the commenting is super fun, right? Like, tell people what you thought about theirs, that encourages more people to put their solutions in because they're getting feedback. And while you're at it, tag me on Twitter at @PWHarris. Or Instagram, Pam Harris_math. And on Facebook, Math is Figure-Out-Able. And use the hashtag MathStratChat. And make sure you check out the MathStratChat problem every Wednesday around 7:00 p.m.
Central Time and pop back here to hear how we're thinking about the problem. Ya'll, we love having you as part of the Math is Figure-Out-Able movement! Let's keep spreading the word that Math is Figure-Out-Able!