How I'm unlearning high school: if x equals y then can we have cake?
I got pretty excited by my last algebra achievement, which was to solve an equation that contained multiplication. Since then I’ve been working through a series of equations on a couple of online platforms that help you break down each step. I’ve managed to follow the procedure for equations with division, such as x/3=5 without completely losing my shit. I may have even nodded sagely as I solved the equation, as if I do this stuff every day.
What still causes me to freeze and hunker down like a rabbit in headlights are the ‘real world’ examples that these equations are presented as. Case in point:
Sam bought 3 boxes of chocolates online. Postage was $9 and the total cost was $45. How much was each box?
This combination of sentences just makes me break into a cold sweat.
The first sentence I am down with. Sam bought some chocolate. 3 boxes in fact. That’s a good amount of chocolate and I approve.
Then we suddenly jump to postage. $9 worth of postage in fact. Me, I’m still over with the chocolate. I’m thinking, was it dark chocolate? That would be good. Or is Sam one of those who insist on doing the whole dairy milk thing. Even worse, is Sam someone who believes that white chocolate is actual chocolate? That would be a deal breaker. Because while I can appreciate that some people need to experiment, buying 3 boxes of white chocolate isn’t experimenting, it’s completely deluded. And then there’s the issue of form. Was it a box of individual chocolates or blocks? And while we’re at it, why was Sam buying 3 boxes in the first place? Is this for a party? Ooh, maybe it’s cooking chocolate for a cake.
You see my problem here?
Then after the postage comes the total cost and I’m suddenly wondering how heavy the chocolate is and whether that’s a sign of the quality of the chocolate or whether the packaging is perhaps excessive and then where would Sam be sending something that ends up costing that much and then I realise that it’s not the postage that cost that much, it’s the whole thing and — heeeeeyyyyyy, here we are finally at the actual question: how much was each box of chocolates?
Meanwhile, my classmates have already solved the problem and have moved on to more important things like world peace and making nuclear power safer.
The bridge I’m struggling to build here is between my narrative, detail-desiring brain and the simple language of algebra which is used to describe the environment around us in a non-literary fashion.
So here’s my first suggestion for the math heads: let’s start with the question first. This is so I don’t get bogged down in background information and start creating wild scenarios in my head. Because the moment I read Mohammed had 15 camels and lived 23 kilometres from his work, I begin to wonder about the cut of his tunic and whether the stitching has been reinforced for hardy travel use. (Ok, I will probably do this anyway. But I may then actually get to the answer, rather than writing a short story about camel-trading).
Like this: how much was each box of chocolate that Sam bought?
And I go: huh? I don’t know. How am I supposed to know? Shouldn’t Sam know that? How many boxes did Sam buy, anyway? You should probably tell me that first if you want my help with any of this. Not that I can help you with this because I don’t math.
And math goes: well, Sam bought 3 boxes of chocolates.
And I go: well, ok. 3 boxes. I hope it was good chocolate. It would be a pretty poor decision if Sam bought 3 boxes of crap chocolate. I would ask for my money back if that happened. Hey, how much did Sam pay for the chocolate? I hope not too much if it was crap chocolate. But maybe it was good choco-
And math goes: well, I don’t know how much Sam paid for the chocolate. And I don’t know if it was good chocolate or not-good chocolate. But I do know that Sam bought the chocolate online. And paid $45 for it all.
And I go: $45? Jeeze, I hope it was good chocolate. That’s a lot of money for chocolate, you know.
And math goes: yeah, but $9 of that was postage, so…
And I go: oh, so hang on, that’s… (does some speedy and possibly not overly accurate subtraction in head) …that’s $36 for all the chocolate then. Mm, still quite expensive. God, I hope it wasn’t white chocolate.
And math goes: yeah, I don’t think it was white chocolate. I mean, I can’t be sure, but that’s my feeling. Anyhoo. Got any ideas as to how much Sam paid for each of the 3 boxes of chocolate?
And I go: yeah, of course. Duh. That’s easy. Cos now that I know what the postage was and can put that aside, I just have to divide $36 by 3, cos that’s the cost divided by the number of boxes and that would then be… (does some more botchy on-the-spot division in head that involves scrunching face up) … that’s $12. $12 a box. $12 a box?! Man, I hope that was some good chocolate!
And math goes: congratulations, you just did algebra.
And I go: huh? how?
And math goes: like this
First step: 3x+9=45 (3 boxes of chocolate + $9 postage = $45)
Second step: 3x+9(-9)=45(-9)
Answer to second step: 3x=36
Third step: 3(/3)x=36(/3)
Answer to third step: (1)x=12
Final answer: x=12
And I go: WHOOOOOOOOOOAAAAAAAAAAAA. I DID ALGEBRA AGAIN.
And everybody is happy.
Unlearning High School is a series published every Monday, Wednesday and Friday. Follow me if you want to unlearn things too or just see how I’m getting on. Comment if you have any tips or insight into the process. Click the green heart to get some chocolate. Well, that part is a white lie. But at least it’s not white chocolate (see what I did there…?)