# Math is Figure-Out-Able!

Math teacher educator Pam Harris and her cohost Kim Montague answer the question: If not algorithms, then what? Join them for ~15-30 minutes every Tuesday as they cast their vision for mathematics education and give actionable items to help teachers teach math that is Figure-Out-Able. See www.MathisFigureOutAble.com for more great resources!

## Math is Figure-Out-Able!

# #MathStratChat - February 21, 2024

In today’s MathStratChat, Pam and Kim discuss the MathStratChat problem shared on social media on February 21, 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.

Kim 00:06

And I'm Kim.

Pam 00:07

And this episode 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

Alright, this Wednesday, the problem was 76% of 88. How would you solve this problem? Pause the podcast, solve however you want. The problem is 76% of 88. Solve it, and then come on back to here how we're going to solve it.

Pam 00:34

Bam! Alright, Kim, I want to go first.

Kim 00:36

Yep.

Pam 00:37

First, I'm just going to say, I was going to play around with finding 8.

Kim 00:43

Yeah.

Pam 00:44

88% of 76.

Kim 00:45

Yep.

Pam 00:46

By finding 8% of 76 to get 80% of 76, and then adding those together.

Kim 00:53

Okay.

Pam 00:54

But I think actually what I would like to do. I am still going to think about 88% of 76. I'm using the commutative property. I'm going to think about 100% of 76, and then back up to 88%.

Kim 01:06

Nice, yeah.

Pam 01:07

100% of 76 is the whole thing. 76. 10% of 76 is a tenth of that. So, 7.6 Or 7 and 6/10.

Kim 01:17

Yep.

Pam 01:17

So, that would get me to 90% if I subtract, so I'm going to actually just do that now. So, 90% of 76 would be 76 minus 7.6, which is 70, 69, 68.4. I don't know if you could tell what I was just doing there.

Kim 01:34

Totally love it. Yep.

Pam 01:35

Subtracted the... Yep. Okay, so that's 90%. Now, I need to get rid of 2%. So, I need to think about what 2% of 76 is. I'm going to go ahead and scale down. I had the 10% already. So, I'm going to scale down to get 1% of 76. That would be 0.76 or 76/100. So, that means that 2% would be... I got to to think for a second. Double 76 is 152, so it'd be 1.52, 2%. So, I've got 90% was 68.4. And 2% was 1.52. Bleh. So, I've got to get 68.4 subtract 1.52. I'm thinking. I'm thinking. I'm going to subtract... I'm going to subtract 1. Nothing else is happening. So, I've got 67.4. And now, I need to subtract 0.52. No?

Kim 02:31

I think something might have gone awry at some point. I'm not...

Pam 02:35

Okay.

Kim 02:35

I'm not writing everything that you said. (unclear).

Pam 02:39

I've got 90%, and I'm subtracting 2%. I think I'm still good. No?

Kim 02:46

Okay. I'm hearing you out.

Pam 02:49

And then, we'll compare to what you got, and we'll see what happens. Okay, so I'm at 68.4, and I'm trying to subtract 1.52. And I think what I might actually do is do 68.4 subtract 2. So, that's 66.4. But I subtracted too much. So, I need to add back, play a little I Have, You Need, I need to add back 0.48. So, adding that back, that would be 66.88. That's my final answer.

Kim 03:21

I sure wish I was seeing your paper.

Pam 03:23

Dang it.

Kim 03:24

I mean, I love listening to you talk out. But this is exactly why modeling is super important, right? Because we have kids talk talk, talk, talk, talk, talk and the others are like, "What?"

Pam 03:35

"What is happening?"

Kim 03:36

Yeah, yeah, yeah.

Pam 03:36

Yeah, yeah.

Kim 03:37

Okay.

Pam 03:37

Yeah.

Kim 03:38

Yeah. It's nice, though.

Pam 03:40

Well, now you have been wanting to go do other. So, I found 90%, and then subtracted 2%. I'm a little curious to now go back and actually add the 10% and the 2% together, and then subtract. I don't know if that would. But you go ahead because if it just didn't work, then we'll have to (unclear) find out, where I messed up.

Kim 03:59

I think you landed where I'm going to land so.

Pam 04:02

Oh, okay. Well, that's a that's a happy thing. Alright, what were you thinking about?

Kim 04:05

So, 76% makes me think of 75%.

Pam 04:10

Ah, of course it does.

Kim 04:11

So, I know 75% of 88 is 66 because a fourth of it would be 22. So, three-fourths of it would be 66.

Pam 04:23

Okay. Nice.

Kim 04:24

And then, if I'm at 75% of 88, I just need 1 more percent of 88. So, 10% would be 8.8. So, 1% would be 0.88.

Pam 04:37

That's so slick.

Kim 04:38

So, then I have 66.88

Pam 04:40

Bam! Well, I definitely think yours was slicker. You win the slick today. Good job.

Kim 04:47

Today. We'll see. We'll see another day. Alright. Fantastic. I hope you share your strategy. What if it was like one of ours? Maybe you did 75%. Or maybe you did something different. Represent your thinking. Please take a picture and share your work. Screenshot your phone. Tell the world. And while you're there, comment on what other people did.

Pam 05:08

Yeah. And like we said today, it's so much easier to actually see what's happening rather than to hear, so we love it when you actually show us what you're doing. While you're there, tag me and use the hashtag MathStratChat and check out the next MathStratChat problem that we'll post every Wednesday around 7pm Central time, and then pop back here to hear how we're thinking about the problem. 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!