super math teacher

The thoughts of a middle school math teacher

Another year finished!

This year has finished.  This morning was the awards and graduation ceremony for middle school.  It was great to see the accomplishments of these students.

This class of students is special for me, since  many of them were in my grade 6 class my first year at AIS.  Over the last three years, I have watched these kids grow and mature.  Even though I did not teach all of them for three years, they will always be a special class to me.  Good luck in High School next year!


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Dam Sen Park Field trip

As the year is winding down, we are trying to finish the quarter with our last units.  I finished with quadratic equations, and students are now watching the movie October Sky, which happens to tie in with the physics unit in science as well.

As part of the unit, we had the opportunity to visit Dam Sen Park, which is a small amusement park in Ho Chi Minh City.  The grade 8 students had a day at the park.  THey had to ride on a roller coaster and the bumper cars.  Anything else they chose was up to them.

The roller coaster is small by US standards.  It has a maximum height of about 50 feet, includes one loop and a corkscrew.  THe entire ride takes about 30 seconds.  While I did   not ride the roller coaster, my 17 year old niece Katie, who is visiting for a couple of weeks, did.  Her reaction was mixed; it was too short of a ride, and she said it was very small.  Of course, she is much taller than most Vietnamese, so the cars were not designed for her long legs.  watching students ride, we noticed the supports actually moved back and forth as the roller coaster moved on the tracks.

She also rode the bumper cars with students.  There were only 8 cars allowed on the racing area at a time, and all were occupied by my group of students and my niece.  It was funny to watch the boys ram each other, while Katie drove idly around.  It was scary to see the sparks coming from the bottom of the cars.  Another not so safe ride!

In addition, there was a haunted house (very tame by American standards), a ferris wheel (can it move any slower?), paddle boats (always popular in Vietnam), the swings, a DaVinci cradle, and a flume ride (can we say slow…..).

I rode the flume ride with Katie and a few students.  OK, no safety bar.  A sign that says remove your glasses and hats (this was not on the roller coaster…..). The boat moves very slowly to the uphill climb.  I think it took 4 minutes to reach the top of the hill.  THen it was around the bend and down.  Splash!  Whiplash!  That says it all!

The highlight was the ice palace.  As you enter, you are given the option of wearing a coat.  Katie and I decided not to, but the students did.  It was a pleasant 32 degrees Fahrenheit inside!  That of course feels great when the outside temperature is about 95 degrees with 90% humidity. Inside were ice carvings of famous buildings, a bar (the kids pretended to be DJs), a pirate ship.  It was great just to be inside, however cold it was!

It was a long fun filled day for teh students.

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Factoring polynomials

I hate teaching factoring of polynomials.  Every year, it is a struggle to get students to remember how to factor the different types of trinomials.  So many rules and tricks!  It is confusing.  This is what I have always heard from students as they try factoring.

This year, I changed my method.  I wish I could take credit for it, but I found it somewhere online.  It is the tic tac toe method.  It works.  And my students actually understood the method.  THey could apply it to all types of trinomials!

I watched mt students during the test.  SOme students knew the other methods for factoring, but most used the tic tac toe method.  Even my students who struggle with math content all year were being successful.  I count this as a win!

The steps are explained in my powerpoint, below.

Factoring polynomials

Here are some samples of my students’ work.



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Adding and Subtracting Polynomials

This activity was done the day before spring break.  We had finished exponents, and were starting the polynomial unit.  I needed to keep my 8th grade students engaged, introduce key vocabulary, and do something that would be kind of fun for them.

Sarah at Math Equals Love wrote about a quick activity that she did a few years ago.  I decided to use her activity.  After reading her blog post, I made a few modifications for my students of higher ability.

Students worked in pairs and received dice and a set of cards with 3 different cards.  hey drew the cards (one from each color) and created a polynomial.  After drawing cards to create a second polynomial, they rolled the dice to determine addition or subtraction. I gave students a recording sheet to show their work.

Since this was essentially combining like terms, something we had done back in September, students were successful after a few minutes.  Most continued to work according to the directions.  However, I have a few students who are of a higher ability.  Therefore, I needed to modify the directions for them.

Thai and Lisa were instructed to draw 2 cards from each color.  This had them combining like terms within their polynomials.  Then they added or subtracted.

As students completed the first time through the cards, they were instructed to mix up the cards and continue.  Some students mixed all the colors together into one stack, and then drew the top 3 cards.  This resulted in polynomials that had different terms.  Combine like terms, fill in terms with coefficients of 0, arrange the cards in standard form……all of these skills were used in the activity.

I would say this was a successful activity.  students were able to add and subtract polynomials that they created.  They demonstrated that they could combine like terms within polynomials.


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Zombie Attack!

Exponential growth and decay can be so boring to teach.  How many times can I use the “start with a penny and double it every day or $1000000” question?

To keep students interested, I related the exponential growth and decay to a zombie attack.  Students who are usually the least interested became the most engaged with this scenario. The start of the lesson just shows a powerpoint slide titled Zombie Attack! with Zombies.  This got the attention of even the laziest students.


Students then worked in their groups through a series of questions in order to determine how many zombies there will be on any given day.  They make a graph, determine the correct equation, and make predictions.  The discussion was definitely at a high level.  All of these are skills needed as they move into high school and the IB and AP courses.  Of course, they must read carefully the information presented in order to determine the number of zombies on any given day.  Students who read the headings of the chart were able to quickly fill it in and start the discussion questions.  Many students just interpreted the chart as how many total zombies (including the original zombies) there were, not how many newly created zombies there were.


Working cooperatively allows students to discuss their ideas.  Those students who are less sure are able to contribute without being ridiculed for a wrong answer.  Seeing students who are less successful become leaders in their groups is rewarding in itself.

This activity is definitely a keeper…..much better than last year’s zombie attack.  Students were definitely engaged and sharing their ideas with one another.

The follow up homework assignment also related to zombies.  Two word problems about zombies….designed to make students think.

After teaching this to all 4 of my classes, students have an understanding of how exponential functions work.  They may not always get the correct answer, but they can identify one given a table, and know what the graph should look like.  They also can see how an exponent can greatly increase or decrease a value.  In addition, through the lesson, they were able to discover that the value can never be equal to zero.  They were able to explain why as well.

This was probably one of my most successful lessons over the past few years.


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Linear Inequalities

Solving inequalities is bad enough…..Which way do I shade the number line?  Is it an open or a closed circle?  Do I need to flip the inequality symbol?  Those are bad enough with one variable.  Change it to having 2 variables, and students immediately panic.

This year, I decided to introduce the concept with a computer activity instead of just teaching how to solve the inequalities.  I love Desmos and the activities that are available at!  My students have worked with some of these activities before, so they knew how to navigate the site.  The 4 new students created an account successfully, and most students rememebred their passwords.

We started with Polygraph, a game similar to 20 questions.  I “anonymized” student names (a feature of teacher.desmos) so that students did not know who they were playing.  They had to ask yes/no questions to determine the graph that their opponent had selected.  This forced students to use vocabulary related to linear graphs, as well as practice their English.  There were the usual random questions that could not be answered with yes or no.  Luckily, there is a choice of “I don’t know” as well.  Once students had guessed which graph they thought it was, they then had to choose 2 graphs and explain why it would be difficult to determine which graph had been chosen.

After about 30 minutes of this activity, students were then asked to switch to  They have used this in class, usually on their device, so they were familiar with it.  They were given a packet of 9 questions and graphs to draw and answer.  My directions were simply “Draw exactly what you see on the screen.”  Many students did not pay attention to the solid and dashed lines.  Some wondered if they had to use the same colors that they saw.

It was an engaging introduction.  The head of curriculum was in the library at the time my students were in the computer lab.  He was impressed that a math teacher would take a class to the computer lab.  He has noticed that I am trying to get students out of the classroom and include more technology, while keeping students engaged.

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Satisfaction: A student returns

Nothing is as satisfying as having former students return to visit.  Yesterday that happened.

Tony, who I taught in Grade 8 my first year at AIS, is now a student in grade 10.  Usually, I see former students in passing, as there is minimal interaction between the High school and the Middle school students (Even though they are in the same building).

Tony saw me during one of my free periods, as I returned to my room.  He asked if he could come in and get some help.  Sure, why not?  I love helping students one on one.

He is studying Algebra II, which has a number of topics that are beyond my realm of expertise.  However, I told him I would try my best to help him.

His question was related to factoring polynomials, something that I taught him when he was in my class.  We worked through the example that he had in his notes, and I showed him a way that I use with my students.  THe method is more visual, and he grasped that quickly.  TO make sure, I had him work through a different example.  THis led to other questions, and he was able to successfully complete the examples I chose.  Hopefully, he remembers these, and applies them to his assignments.

The visit was a short one, and we focused on Algebra.  But it was satisfying to have s student return and get help, even though I am no longer his teacher.

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Scatter Plots and Measurement activity

Scatter plots fall in the unit of Linear equations, but can also stand alone.  In my classes, we have already had our assessment (Mathematica City Map – I already wrote about that).  Since we only had 4 class periods between the Christmas break, and the Lunar New Year Break, I decided that Scatter Plots would be a good way to finish the time.

To start the lesson, I had the students collect a series of measurements from their class: height, armspan (aka, wingspan), forearm length, handspan, wrist circumference, and neck circumference.  Students were not told why they needed these measurements; only to get them, working with a partner.  They were only allowed a pencil and a measuring tape.  The measuring tape was only 150cm; many of my students are much taller than that.  It was time for problem solving!  In the case of this activity, teamwork and communication was important!

Students had fun collecting the measurements.  No one choked anyone (always a good day in grade 8 when no one gets hurt!)  students chose who they wanted to work with.

After collecting the data, it was time to make 3 different scatter plots: Height v. Wingspan, Handspan v. Forearm length, and Wrist circumference v. Neck circumference.  Students did not know any more than that.

The second day of the lesson had students compare their graphs within their small groups.  They noticed that the graphs were similar.  We then discussed what a scatter plot was, as well as correlation and the different types.  Students then decided that there was a positive correlation for all 3 graphs.  They also noticed that some students seemed to be outliers, because their data point was not in close proximity to the rest of the data.  We discussed how this did not change the correlation.

After the lesson, students were then given 2 more data sets and asked to graph and then determine the line of best fit.  Since we do not use graphing calculators (that is in the high school), students had to decide where the best place to draw the line was.  Then, using their lines, they had to calculate the slope and determine the equation of the line.  This related the scatter plot ;lesson to the rest of the unit that had already been taught.

This lesson was a fun one for students.  They were able to be successful in both parts of the lesson, and it was a great way to finish the few days between breaks.

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Mathematica City Map

I LOVE teaching linear equations and their applications.  In this case, it is unit 5.  I enjoy the applications and the different ways to write equations.  Slope, y-intercept, graphing,….all of these are important and can be fun.

My assessment for this unit is not a traditional test.  Rather, I have the students create a map of the fictitious Mathematica City.  Of course, all the streets and locales they must put on the map are related to math.  This usually gets a chuckle from some students.

Today, 2 classes started the map in class.  One student was creative in how he labeled the x and y axes. (see photo below)  I had to take a picture of it!  Of course, in all my years of teaching algebra, this is the first time I have ever seen a graph labeled this way!


The activity really shows me if the students know how to graph on the coordinate plane.  For many of my students, if they have come from traditional Vietnamese schools, this is a gap that I have to fill in while still managing to teach my Algebra curriculum.

They also have to manipulate the equations into the different forms.  Reading the directions carefully is also important.  Students have to look for words such as “parallel,” “perpendicular,” and “intersection” need to be understood in order to draw the lines.

I stress that this is something students should take their time with.  Using their ruler and carefully drawing the lines will make the interpretation portion easier.  It also makes for a neater map!

The kids were definitely engaged throughout the period.  Questions that were asked were relevant, instead of the usual “I don’t get it.”  Even my 2 new students, who started just last week, were engaged and being successful, with minimal help from their groups or myself.


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Viva Espana!

This post has NOTHING to do with math or middle school. (Well,. it does mention geometry, briefly….)

I just returned (literally 12 hours ago) from my 2 week vacation through Spain and Portugal.  After spending the last 2 Christmas seasons in the tropics of Vietnam (with family visiting each year) I decided that I needed a change of season.  Spain and Portugal would be just that…..Cold, but not ice and snow.  They were the perfect choice.

My flights were via Dubai… amazing airport.  We flew right over the Palm islands of Dubai.  I had a window seat and could see them.  Sorry, but no pictures of the Palm!  I can, however, highly recommend flying Emirates Airlines…..even in economy, it was better than other airlines I have flown.  Service was amazing, and airline meals were actually decent (not great, but decent).


This is at the M&M store in the Dubai airport…..The little stuffed dog is my traveling companion, Spike.

I loved my time in both countries.  I was on an organized tour, something I normally don’t do.  However, because I had never been to Southern Spain before, or Portugal, I decided this was the way to go.  I would see a lot, and someone else could do all the arrangements and translating (in Portugal anyway; I speak Spanish).

Amazing sites, but I could have spent more time in Lisbon and Salamanca ( I would have loved to see the university there…).  And so much geometry….in the Alhambra in Granada and in the Moorish architecture of Southern Spain.  I must admit, I took quite a few pictures of the geometry!  I was finding math everywhere!


This is the entrance to the park, across the street from my hotel in Lisbon Portugal.  Love the geometry!

Monday is a return to school, for exactly 2 weeks.  Then it is another 2 week vacation, because of the celebration of the Lunar New Year (aka Tet holiday here in Vietnam).  Yes, I will be traveling, this time to England and Ireland.  Yet another serious change of season.  I am looking forward to it!


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