Hey, fellow mathematicians! Welcome to the podcast where Math is Figure-Out-Able. I'm Pam.
And I'm Kim.
And this is a MathStratChat episode where we chat about math strategies. Every Wednesday evening, I throw out a math problem on Twitter, Facebook, Instagram, all the social media, and people from around the world chat about the strategies they use. We love seeing everyone's thinking!
We sure do. So, this Wednesday, our math problem was 75 times 24. How would you solve this problem? Pause the podcast, solve it before you tune into listen again. The problem was 75 times 24. Solve it, and then come back to here how we are going to solve it.
Alright, Kim, I'm going to go first today.
Okay.
So, I'm thinking about 75 times 24, and for whatever reason, today, I was just seeing less 100. I was thinking Over. And I'm not sure if it's because...
Oh, alright.
...I knew I was talking to you or not. But alright, so how I was thinking Over was I thought, if I can find twenty-five 24's, then I could just remove those from one hundred 24's. Because then one hundred 24's minus twenty-five 24's would give me seventy-five 24's. So, I'm going to find twenty-five 24's by thinking about a fourth, one-fourth of 24. So, a fourth of 24 is 6. So, if I scale that one-fourth up to 25, that 0.25 up to 25. I multiply by 100, then I multiply 6 times 100, that's 600. So,
twenty-five 24's is 600. And one hundred 24's is 2,400. And then, I kind of just was like 24, 6. 24 minus 6 is 18. But I'm in the hundreds, so it's 1,800. And at that point, I was like, "Oh, duh." So, twenty-five 24's was 600. I could have just scaled that times 3.
Nice.
600 times 3 to be 1,800. Either way, kind of finding a fourth of 24 to help me get twenty-five 24's, and then using the twenty-five 24's.
Yeah.
Cool.
Nice. For whatever reason, this time, I did not think about quarters, even though the 75 is screaming quarters. I actually was thinking about factors for this one.
Huh.
So, I thought about 75 being 3 times 25. So, on my paper, I wrote 3 "dot, multiplication symbol" 25. And then, for 24 I wrote 3 times 8. So, I have 3 times 25, times 3 times 8.
Okay.
And then, I just rearranged them. So, I thought 8 times 25 is 200. So, maybe I did think quarters because 4 of them would be 100. Another 4 would be 200. So, 25 times 8 is 200. And then, I have left the 3 times 3, which is 9. So, 9 times 200 was your same 1,800.
Cool. So, you can factor the factors and rearrange them using the associative property, and then Bam! Find a nicer way to multiply them out.
Yeah.
Super cool.
I love this problem. There are so many good things to do. My brain is swirling. But we want to see what everybody else is doing, right? So, we can't wait to see that. If your strategy was like one of ours, very cool. But there's some really cool stuff to do that's not like what we're thinking. So, represent that thinking and comment on other people's as you share that on social media.
Super cool. And tag me on Twitter at @PWHarris. Or Instagram, PamHarris_math. And on Facebook, Math is Figure-Out-Able. Use the hashtag MathStratChat. And make sure you check out the MathStratChat problem that we post on Wednesdays around 7pm Central time, and then hop 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. Keep spreading the word that Math is Figure-Out-Able!