Really clear explanation of how Warren Buffett's investment strategy creates high returns year after year.

# Category Archives: Uncategorized

## How much does it cost to buy an insurance carrier to get started down the path of executing the Warren Buffett strategy?

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## Expeditionary Learning Through 17-Year Cicadas

If you live on the East Coast, chances are you’ve heard about this summer’s emergence of Brood II cicadas. Cicadas are winged insects that live underground most of their lives, sucking on the xylem (sap) from roots of trees. When the ground temperature 8″ below the surface reaches 64 degrees Fahrenheit, they will emerge and transform into their final adult form. They ascend into nearby trees, shed their skin one last time, grow wings, and set off to mate. Some species are annual cicadas and emerge every year. However, Brood II cicadas only emerge every 17 years and do so by the millions.

I teach at an Expeditionary Learning school, and teachers are encouraged to design curriculum through expeditions. Expeditions are rich units that engage students by investigating some compelling question(s). When I first read about the 17-year cicadas that would swarm North Carolina to Connecticut, it seemed like the perfect topic for my sixth grade math students.

We began the unit by Building Background Knowledge. First we listened to audio of the male cicada mating call. Students wondered what it could be, and then we showed them the associated video. We watched another video and discussed some cicada facts. Then students created a KWL chart of what they Knew and Wondered. (Later, we would add the other things the class Learned). Our guiding question was, “Where can we find mathematics in nature?”

The guiding question led us to explore why periodical cicadas only emerge every 13 or 17 years. We looked at the Sieve of Erastosthenes, prime numbers, factors and multiples. Then we practiced converting between fractions, decimals, and percents by creating surveys and representing the results in various ways. Students wanted to know if they could outrun a swarm of cicadas flying towards them, so we went outside and measured how fast different sixth graders could run. We explored measures of central tendency to see how fast an “average” sixth grader was. Finally, we looked at a cicada cookbook and practiced scaling recipes. **Here is a link to many of the resources I used for this unit.**

Students were disgusted and enthralled by the idea of eating cicadas! It was unfortunate that they made such a minimal appearance in New York City, especially after all of my build up. Fortunately, they did emerge in large numbers in Staten Island, so I took a trip to harvest enough Brood II cicadas to sate my students and colleagues! Here are some pictures of the preparation.

Anyone brave enough to eat one earned a button that became a badge of honor. (Thanks to Maurice Principe for designing them!)

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## Students without Supplies – Pencil Problems

One of my favorite math bloggers, Sarah, had a great post recently about pencils. It was serendipitous, since I’d just had a conversation with a first year teacher about school supplies. Her lesson came to a halt because students didn’t have loose leaf paper!

I, too, am always baffled when students don’t come to school with what I consider basic supplies. For me, the battle this year has been with pencils. At the beginning of the year I had a bin of maybe 50 golf pencils. They’re distinctive, don’t have erasers, and students really don’t like them. My supply lasted several months, disappearing little by little, until one day I was out for Professional Development. Upon my return, the whole supply was gone, along with my stock of erasers.

I had a discussion with each class, reminding them that I had paid for those supplies so that students could borrow them during class. I wasn’t going to go out and pick up more, so now everyone would need to be prepared for class. The unfortunate consequence was students going around trying to borrow a writing implement from classmates 10 or 15 minutes into the period!

So I tried collecting the pencils students left behind: a sort of “take-one, leave-one” system. The obvious flaw here is that a student who doesn’t have anything to write with in math is going to have the same problem next class as well. It ended up being more of a “take-one” system. The whole thing would’ve collapsed within days if not for one valiant student who brought me several pens and pencils a day! Alas, I needed a better solution.

Finally I bought a hundred pack of Ticonderoga pencils from Amazon. The next time a student needed a pencil, I told him that I’d sell him one for 25 cents. At first, a few students were outraged that I was selling them pencils. So I reminded them that I’d already bought a class set of pencils and erasers that had all gone missing. I wanted to make sure they were prepared for class, but I can’t afford to buy school supplies for over one hundred students.

It’s been almost two months now, and students have requested that I add erasers and sharpeners to my store! I sell them basically at cost, which doesn’t seem to trouble kids who already spend several dollars a day on candy and bottles of Arizona. Last week I had to make another order to restock my store, but I no longer feel angry or frustrated when students don’t have pencils–I just sell them one.

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## Multiple Methods of Explanation

Alex* did both worksheets today, however his sense on how you’ve taught him to convert whole numbers into fractions appears to be different than what I know (keeping whole number as numerator and making the denominator 1). I think he must have been confusing whole number conversions with something else you were teaching but he was obstinate. Thus I think he had trouble with the generic rectangle calculations and I could not help him and we lost patience with each other.

Perhaps you can revisit whole number conversions with him as he would not believe me. I’ll have him do the three problems once he gets the concept correctly — or that you confirm that in this case I am smarter than a 6th grader….and if I am not, I am so sorry. It is probably better I write for a living.

*Not his real name

Don’t worry, you’re certainly smarter than a 6th grader. Certainly more wise, too, because 6th graders have a problem not realizing what they don’t know.

I haven’t taught students that they can write any whole number as a fraction over 1 (e.g., 4 = 4/1). As you realized, they sometimes don’t “get” why it works and end up getting more confused. Currently we’ve just been reasoning through multiplicatively via repeated addition: for example, if you had 4 times 2/3, that just means 2/3 + 2/3 + 2/3 + 2/3. To go further, drawing a picture of 2/3 four times and then counting the pieces to recognize you’d have 8/3. A lot of students are still struggling with the idea, and want to say the answer is 8/12 (because they multiply top and bottom by 4). But then you can present them with the question: Aren’t 2/3 and 8/12 equivalent fractions? This creates the dissonance for them to see that the answer should be

morethan what they started with, not the same. Put another way, multiplying by 4 changes the number of pieces you have (the numerator), but not the size of the pieces (the denominator).He’s okay right where he is–a lot of students are still there, since we only just learned how to multiply fractions. We’ll be doing more work multiplying fractions by both fractions and whole numbers via the mixed number generic rectangle problems. I think with concepts like this, it’s important to foster both a continual emphasis on

why the answer makes sensein addition to repeated drill, which gives students several times to make mistakes / correct them and notice the patterns themselves.If he wants, we could do some problems together at lunch. I often have a few kids up for extra practice / more individual instruction.

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## Starting Strong!

*Teach Like a Champion*) that I knew was ideal. A perfect cocktail that my first-year self had no idea how to brew.I also understand the importance of routines and procedures and how to teach them. Teach for America mentioned them, but I don’t feel like I really learned them. There’s so much going on in a classroom that experienced teachers forget all they’re doing. And to an untrained first year, these things are

*invisible*. It’s like discussing thick/thin contrast on the rounded letters of a font. Most people have, at best, an unconscious recognition of these things.

But knowing how important the start of a class is and making it priority number one at the beginning of a year. It’s the first thing you do with students every period. If you set the tone well at the beginning, they fill in the blanks and end where they expect themselves to be. People are predictors, constantly imagining how things *should be*. As mentioned in Steve Pavlina’s recent post, the essence of frustration is when our predictions don’t match reality. So teaching kids how things should begin is half the battle.

I’ve recognized a few things that work really well with my 6th graders:

- Having them line up outside, tell them a preview of what they will do when they come in, and making sure it’s purposeful and strictly timed does wonders for those first 5 minutes. In my class they have 4 things to do:

- Take out their HW and HW trackers (a weekly sheet that I stamp daily, with a rotating quote, and space for parent communication)
- Write down tonight’s HW in their planners (keep this short, because 6th graders are notoriously slow writers)
- Check their answers against the posted HW solutions
*OR*Complete the Do Nowset up a new entry in their ISN (Interactive Student Notebook)*OR* - Review your work with your teammate, & see whether he or she is ready for class.

- If it’s a minute into class and I’m still waiting for students to take out HW trackers, I know it’s because they’re unfocused. We line back up outside, I reiterate that they weren’t meeting my expectations, and then I send them in with the assurance that they can do a better job. Some days I’ll use a timer and report their start-up time, challenging them to improve tomorrow. (Maybe I should be more consistent about this?)
- Students know the HW tracker is a big deal. They’re responsible for it for the whole week. (I print it on bright yellow paper, to tilt the odds in their favor!) If they lose the tracker, they lose credit for the HW. (Our math department’s policy is that late HW is not accepted, because the point is that it’s daily spaced practice.) The other piece is that I only grade HW on effort:
- 2 – Attempted Everything
- 1 – Partial Effort
- 0 – Little to No Effort

- I stamp every student’s tracker daily. By personally coming by and checking, I create a personal obligation. I want all of my students to do HW, I believe it’s valuable for them, and I’m disappointed when they didn’t do it. Telling them I know they can do better tomorrow and regretfully having to stamp that 0 kills me inside. But I’ve noticed that HW completion is higher than it’s ever been in my past two years.
- Finally, I have these chimes for the classroom. I hate countdowns; they feel so authoritarian. I’m not really a “clap twice if you can hear me” kind of guy; I think those sorts of calls to order often release too much energy. But the kids seem to like the soothing tone (I certainly do), and I can hit them quickly or slowly. I taught the class that my expectation is that by the time the third chime sounds, everyone is silent. I gave more space between strikes early on, to build success. Now I can hit the first two quickly and pause an instant for the third chime, until the room is silent. They always see themselves quieting just in time, and then I compliment them and move on quickly.
- As a side note, my first year I borrowed something from the 7th grade teacher. She would whisper “Good morning, class” And they would whisper back, “Math is life.” Then she would speak it loudly and they would echo in turn. I tried to do that with my classroom motto, “Strength in Numbers,” but I didn’t pull it off as well with my 8th graders.

So that’s the start of my class. Then we’re off into the day’s lesson. And each day keeps getting better!

Next post, I’ll talk about the management strategies I’ve found successful during class.

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