Check My Arithmetic

Wednesday. Sophomore math, eighth period. 

While most of Mr. R's classes are co-taught, his eighth period is not, which means that I get to teach it. Woo-hoo!

They just started a unit on geometry. (Back in the day, freshmen took algebra 1, sophomores took geometry, and juniors took algebra 2. Nowadays they've mixed all the topics up and distributed them over the three years differently.) We did a day of definitions (which they should have learned the previous year), and on this day it was time to go over some problems having to do with those definitions. 

I showed the kiddos how to set up one of the problems. I gave them some time to try it out. And then I worked it out with them to make sure they knew what they were doing. 

As I worked the problem, I got to a point where I had to subtract two numbers. And I paused. 

I tell this like a joke, but it's true. I got through calculus just fine, but I stumble when it comes to arithmetic. 

I mean, I can add, subtract, multiply, and divide. But not fast, and not well. 

Give me an algebra problem, and I have no problem. Geometry is even easier. I took four semesters of calculus in college. I majored in physics. I can do the math. Just not the arithmetic. 

I was trying to subtract two numbers in front of the class. It was something like 123 - 15. The mental gymnastics weren't happening. A student helpfully provided me with the 108. 

And so, I admitted my problem. I told them, "Seriously, check my arithmetic." 

I figure it's better to admit it. They all use calculators, anyway. I'd rather they catch me if I write down the wrong number. If they let me know where I made an error, I can fix it right away, thereby not confusing them with mistakes. 

As I proceeded through the page of problems, I made sure to check the key, just in case. I didn't make any major errors. I miswrote a bunch of things (I wrote a 6 when I meant to write an x), but I got the arithmetic mostly right. 

Still, I'll never entirely trust myself. It's too easy for me to slip up. 

Today's A to Z Challenge post brought to you by the letter

Bait and Switch?

 

I have five chemistry students, but the school had no chemistry books. I made do with some intro to chemistry online assignments for the kiddos. But then the chemistry books arrived, and I could delve into them. 

So, it was last Thursday before we really got into some real chemistry work. It was the section introducing problem solving in chemistry. 

"We're doing math in chemistry?!?" 

Massey was incensed. I suppose he thought he only had me for one math period. 

I calmly explained that yes, math would be required for chemistry. That we would be solving problems. 

Oh, they didn't like that. Not at all.

Miscalculated

For Christmas, my niece wanted a beanie like one she'd seen online in periwinkle. Okay then...

Yes, Christmas. I really only started my Christmas knitting after Christmas, so all those gifts are late. And yes, this is the niece of the gray behemoth from last year. 

From the picture (which I'm linking to only out of copyright concerns), I could tell it was a rather fine yarn knit in a one by one ribbing. But finding the color periwinkle proved to be a challenge. Ultimately, I had to search "periwinkle" on LoveCrafts.

I swatched. That just means I cast on a small number of stitches and worked them in pattern for a bit. I know how many stitches I cast on. I measured the piece. I know how big I want the finished beanie to be (niece's head was measured), Just a bit of math told me how many stitches to cast on.

From the picture, I could tell they used a tubular cast on. (These were machine knit, I'm sure, but I can still replicate in hand knitting.) I've never done tubular cast on before, but I have seen it done and I can follow directions. (Every technique is demonstrated somewhere online. That makes picking up new skills easy.)

It turns out that the tubular cast on is a bit complicated. You have to use a provisional cast on, then work five rows in a specific manner and... (If you're interested, you can see a video of this here.)

I set aside an afternoon just to cast on. It took me two and a half TV shows to complete, but I managed it. Then I joined to work in the round. And that's when my sneaking suspicion proved to be correct...

My hat was way too big.

For comparison, the above image has an actual head-sized beanie next to it. (It's more of a child size, but child size versus adult size isn't that much different.)

Deep sigh.

There's nothing for it now. I have to frog it and start over.

I mean, unless you know a giant that wants a beanie. In periwinkle.

I sat down to recalculate. Because somewhere the math went wrong. And that's when I saw it.

I had done the math correctly. Alas, when using niece's head measurement, I transposed the digits (instead of 23 inches, I calculated 32 inches). Someone, ahem, wasn't paying attention...

Considering how many times I gently correct students in math class with, "Does that number make sense?"...

Avoiding the Art

Special ed geometry. It was a good sized group, and they had an assignment that I thought was pretty cool.

They had been learning shapes--the specific shapes that one learns in geometry. Not just your garden variety square and rectangle, but the parallelogram, the rhombus, the kite, and the trapezoid.

The assignment had them using at least one of each in a design that they were to come up with. They got to draw it, color it in, and make it as creative as possible. The idea was to make it like a tile.

I passed out the assignment. And every single one of them turned it over to the back, where there was a word search.

I explained the assignment. It was fun! They got to draw. They just had to use the correct shapes. (I'm not much of an artist, but I would have loved an assignment like this.)

Them? They kept working on the word search.

So, I explained that the word search wasn't their assignment. Nope. It was worth nothing. The art project, however, was what they needed to do.

Reluctantly, they turned over the papers. Grumbled. Sketched out something. Complained that they'd rather do the word search.

via GIPHY

Some days, I wonder about them.

Have you ever thought something was so cool, but when you shared it with someone else, they looked at you like you were crazy?

Today's A to Z Challenge post brought to you by the letter...

Stuff We'll Never Ever Need

I used to have a MySpace account.  I started my blog there.  But after I had a few too many technical difficulties, I moved the blog here.  I have since closed the MySpace account.  I hate to lose all of my blogs from that time, so from time to time I repost them here. 

This one was originally posted on July 2, 2007.  I think it's apropos as I'm about to make another batch of these cookies (in a day or two).    

I am planning on baking some chocolate chip cookies.  (You know which recipe.)  It was suggested to me that to streamline this time-consuming activity that I should do the pan cookie variation.  I thought that this was a good idea, so I looked into it.

The recipe calls for a 10 x 15 inch jelly roll pan.  First I had to figure out what a jelly roll pan was.  Once I realized that I had one I measured it.  It's 12 x 17 inches.  And this is where the math came in.

Okay, so first thing: I double the recipe.  That means that this will fill two 10 x 15 inch jelly roll pans.  So, the recipe fills an area of (10 x 15 = 150) 150 square inches.  Double that--300 square inches.  My pan has an area of (12 x 17 = 204) 204 square inches.  So, too big for a single batch, not quite big enough for a double batch.  What to do now?

I went searching for a smaller pan to make up the difference.  I had a small cake pan, but that would only give me 45 square inches more.  300 - 204 = 96.  That was not quite half.  And then I found the pie pans.  Oops.  Now I have to remember the area formula for circles (actually, not an issue--I just hate bringing pi into the equation).

Right, so the pie pans give me roughly 33 square inches (not an exact figure because of the previously mentioned pi).  I have several, so three should do the trick (or at least make it close enough).

Sigh.  Baking should not be this complicated.

I sub for math classes a lot.  And someone always complains: "We'll never need to use this stuff."  I have told them otherwise, but they don't believe me.  I've given up the argument.  But they are wrong.