Math is Figure-Out-Able with Pam Harris

#MathStratChat - February 21, 2024

February 21, 2024 Pam Harris
Math is Figure-Out-Able with Pam Harris
#MathStratChat - February 21, 2024
Show Notes Transcript

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

Pam  00:37
First, I'm just going to say, I was going to play around with finding 8. 

Kim  00:43

Pam  00:44
88% of 76. 

Kim  00:45

Pam  00:46
By finding 8% of 76 to get 80% of 76, and then adding those together. 

Kim  00:53

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

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

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

Pam  03:37

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!