# Episode 14: Guess my Number

September 22, 2020 Pam Harris
Math is Figure-Out-Able with Pam Harris
Episode 14: Guess my Number
Chapters
Math is Figure-Out-Able with Pam Harris
Episode 14: Guess my Number
Sep 22, 2020
Pam Harris

Pam and Kim have some fun this episode as they read out a submission from Aaron Houston about his mathy dad. They talk about the kinds of things parents can do with their kids to have fun mathematizing!
Talking Points

• I Have, You Need
• the Guess my Number game
• How do you think about finding Prime Numbers?
• Math can be fun!

Pam and Kim have some fun this episode as they read out a submission from Aaron Houston about his mathy dad. They talk about the kinds of things parents can do with their kids to have fun mathematizing!
Talking Points

• I Have, You Need
• the Guess my Number game
• How do you think about finding Prime Numbers?
• Math can be fun!
Pam Harris :

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

Kim Montague :

And I'm Kim.

Pam Harris :

And we're here to suggest that mathematizing is not about mimicking or rote memorizing, but it's about creating and using mental relationships, empowering teachers and students. We answer the question, if not algorithms, then what in the world are you gonna do?

Kim Montague :

Welcome to this week's podcast, y'all. Thanks for joining us. A few weeks ago, we asked you to share someone that you know who you think is one of those mathy people.

Pam Harris :

And y'all we got a fantastic email from our friend Aaron Houston. And we had a blast talking about the stuff that pinged for us. So Kim, tell us how he started this email.

Kim Montague :

Pam Harris :

Yeah. So Excellent. So he gets an opportunity to do some math right then in there try to convince you of his choice and so he has a reason right? It's a reason for him to actually do some computation. That's awesome. Hey, let me tell you what else Aaron said. So he said, quote, when we were really little, he meaning his dad would give us cash to pay the bill. But we had to figure out what the change would be first.

Kim Montague :

Oh, nice.

Pam Harris :

And he says I know my compliments of 100 because of this unquote. So Kim, it's I have you need, right there in the restaurant that's so awesome. The partners of 100 are so important. What a great way to get your kids involved that they get the change as long as they can figure out what the chang is. Amazing. So y'all, if that's new to you, if you've never heard of us talk about I have you need the routine that Kim made up that we love it helps kids develop partners of 100 like if I have 47 what do you need to make 100, So if I have 47 you need 53 to make 100. If you want to hear more about that, you can check out Episode Seven called one thing mathy people do, where again, we talk about helping students develop partners of 10, hundred and 1000. And how those relationships show up everywhere so that knowing them can really help you do more math.

Kim Montague :

Can I just mention too, that you talked about I have you need in your multiplicative reasoning online workshop, and I'm having the blast, a blast reading comments from people who were thinking about other partners that they want to build, like 60 for time 180 for triangles, 360 for circles, and it's just got me thinking about what other compliments do we want to encourage people to make sense of?

Pam Harris :

Oh, nice, nice, good. Okay. Cool. All right. What else did he say?

Kim Montague :

Aaron also wrote that when we were a little older, he would also let us guess the price of the meal, which is brilliant. I might guess \$25 and 83 cents, and he would tell us how many numbers we had correct? Like how many digits were correct. So that my brother would guess \$25 and 25 cents? And he would say that no numbers were correct. So each time they guessed the dad would tell them how many numbers were correct. Maybe then I would guess \$36 and 71 cents and two numbers are correct. And this would go on until we had all four numbers and then we were just working through different permutations for the what those four numbers were.

Pam Harris :

Oh, my goodness, that's the game Mastermind. I loved that game growing up. In fact, I have that - we have that game in our game closet right now. That's an amazing game to get kids messing around with permutations because you tell them which numbers are right and then what places right.

Kim Montague :

I totally forgot about mastermind. I remember playing that game so simple and so cool. And I played it as a kid. I'm traveling with my parents. I remember my mom pulling the game out. We were going on camping trips, and the colors right? With the pegs?

Pam Harris :

Yep, yep totally. Yeah and you totally put like the white color for if you have the place right and the red color if you have the the color right but not in the right place. Yeah all the things. So what a cool way to play mastermind when you're out with your kids by guessing the amount on the bill that's excellent way to go Aaron's Dad. So let me keep going. Aaron also said quote other times he there dad, he might just think of a number between one and 100 or a number between one and 1000. And we would guess and he would tell us higher or lower as we guessed, and narrow it down to the answer. Kim you play that game all the time!

Kim Montague :

I do. I do play guess my number. And we added things like if the numbers are odd, or what is this the sum of the digits? I wouldn't ever just let them go like higher lower, higher lower.

Pam Harris :

Let me tell you, when I began to play this game, I totally would just have kids guessing numbers. And then I would say, my numbers higher than that number, and then they would say, okay, they would choose a number higher. And then I would say, No, my number is lower than that number. And then they would choose the number lower. And I totally thought I had the corner on this game. And then one day, I heard you playing with your kids. And I was like, Ah, it could be so much better because you added so much like tons more mathy things because as your kids got good at it, then they could sort of bring in more math things. And I thought it was a really natural way for you to bring in some vocabulary that your kids can kind of get used to. Alright, so yes, I want to play.

Kim Montague :

Well. Yeah. And let me let me add to that as, as my kids have gotten older, we still continue to play, but not only have the size of the numbers that I give them increased, um, there's more questions that we can ask each other, right? They know more content now. So we can bring that in. So let me let me just tell you, we can either play where I give you clues. But it's also fun for me to just think of a number and you have to ask things about the number I'm thinking of.

Pam Harris :

Okay, so let's try that way. Okay. So all right, you think of a number? And y'all we have not done this ahead of time. Live on the Air mathematizing. Here we go. Okay, Kim,

Kim Montague :

I've got it

Pam Harris :

Is your number between zero and 100?

Kim Montague :

No.

Pam Harris :

Is your number greater than 100?

Kim Montague :

Yes.

Pam Harris :

Kim Montague :

No

Pam Harris :

Is your number a whole number?

Kim Montague :

Yes.

Pam Harris :

Okay. So it's a whole odd number greater than 100. Is your number less than 1000?

Kim Montague :

Yes.

Pam Harris :

What is the sum of the digits of your number?

Kim Montague :

Eight. You're going really fast here. Can you slow down and let people think?

Pam Harris :

Sorry.

Kim Montague :

That's a great question.

Pam Harris :

I'm excited! Okay, so whole number. It's odd and the digits sum to eight. So is your number 701?

Kim Montague :

No.

Pam Harris :

Kim Montague :

Ooo. I love that you did that. It was a huge moment when my youngest figured out that that was a thing, right? So no, it's not 107.

Pam Harris :

Is your number a permutation of seven zero and one, like 117?

Kim Montague :

No.

Pam Harris :

Okay, so I have the wrong, odd numbers. Is your number bigger than 500?

Kim Montague :

No.

Pam Harris :

Is your number bigger than 250?

Kim Montague :

No.

Pam Harris :

Okay, so it's between zero and 250? No, it's between 100 and 250. That's odd. It's odd. Um, what else could I ask? Here, I'm gonna ask this question, Kim. What would be another good question for me to ask?

Kim Montague :

Oh, you could ask if it was divisible by something or if it was prime or composite.

Pam Harris :

Kim Montague :

It is.

Pam Harris :

Okay, a prime number between 100 and 250. I bet you anything people are listening this podcast and like screaming numbers at their phone right now they're like try 117. Oh except 117 wouldn't add eight but 100 Let's see. Ah 100 and... Has to add to 8... 124 Nope, that's even. 133.

Kim Montague :

No, that does not sum to eight.

Pam Harris :

Oh duh... 143

Kim Montague :

Correct.

Pam Harris :

Are you serious!?

Kim Montague :

I'm serious! Yah I answered the question really quickly: Is it is it prime or composite? Is that, that's prime right?

Pam Harris :

Well, that's a good question like so Kim, what are you thinking right now to determine if 143 is prime?

Kim Montague :

Well, I'll be perfectly honest with you. The first thing I thought was it's not divisible by seven because 20 times seven is 140. So I left sevens alone.

Pam Harris :

Nice. First thing I did was think if the sum of the digits are eight, then it's not divisible by two, no, that by three, six or nine, because the sum of the digits is eight, right? So that's, I know those. I also knew it was odd. So it's not divisible by two, right? or four or 8. Uh.. 11. Is it divisible by 11? Because it has that pattern that o of 11 sometimes have right? So is it divisible by 11?

Kim Montague :

Is divisible by 11. 13 times 11. Golly I was totally wrong. So yeah, math teachers were wrong.

Pam Harris :

Hey, hey, but

Kim Montague :

We learned something! I need to do 11s more.

Pam Harris :

So we're not failures, right? Because in a huge way, what we just did was have fun figuring out if 143 was prime. Yeah. And a relatively new pattern for me is this pattern of 143, where it's sort of add the one and the three together to get the middle four has something to do with multiples of 11. And that's a relatively new pattern I've just been able to sort of recognize, which made me then wonder if it was a multiple of 11. But even as we're just discussing the kinds of things that we think about to determine if that number was prime, I think kids can learn from that and so it's not a fail at that point. Then we can sort of poke fun at each other and go, Oh, it isn't prime. But we had a blast playing the game and we learned something about 143 What were you gonna say?

Kim Montague :

I was gonna say if Luke were here, he would he would have told me that I was wrong.

Pam Harris :