SamizdatMath

Are you teaching the quadratic formula to your students? Are you teaching it the same way you learned it in high school? Or maybe college? Or maybe on the street somewhere? Then you're probably teaching it WRONG AF. It's okay: I've been teaching the quadratic formula WRONG AF for decades. I didn't know it, but I was. It wasn't until one day I was working with a group of my college students and made a mistake that I had a realization: we've been teaching the quadratic formula WRONG AF for decades

To quote Charles Dickens (from The Pickwick Papers) “What fresh misery is this?” This is what happens when you have time on your hands and you’re thinking to yourself, “well, how can I bring bles’sed torment unto my students this week?” Many (many) years ago I had a student in my sixth grade class (you probably had them) who would respond to any “do now” problem with a quick look and the brag “oh, this is so easy!” And then after fumbling his way through 3 or 4 methods, all featuring a lapse of

Here's the problem: There are 100 seats on an airplane and 100 people waiting to get on. The first person loses their boarding pass, so they take a random seat on the plane. If the next person finds their seat occupied, they take another random seat. If their seat is free, they sit in it. Question: What is the probability that the 100th person on the plane will sit in their assigned seat? Oh, sure, you can look up the answer and come up with some convoluted or excessively mathematical explanati

This is a seven part investigation into the carbon footprint of different kinds of food and diets. Investigation #1: What We Emit When We Eat: This is a list of 20 different foods, including meats, dairy, vegetables and grains and the amount of carbon released during their production. Students calculate the equivalent in miles driven by a car, as well as the amount of carbon released per ounce. Investigation #2: Students investigate the carbon footprint of three different meals. The first is a s

This is an activity that teaches students to classify acute, obtuse, straight and right angles using semaphore flag signals. Why semaphore flag signals? Because they're fun, interesting and "real." And also, they're a good example of how to teach a concept beyond the "prototypes." What do I mean by this? Well, do an image search on "right angle" and you'll see that the examples that show up are "textbook prototypes." That is, they all have a side resting on the horizontal, the other on the verti

This is a set of activities that uses the raw data from each state in the 2016 United States Presidential Election, including the number of votes for each candidate, the number of "eligible" voters and the number of voters who "did not vote." What students will find out that if "did not vote" was a candidate, it would have "won" by one of the largest landslides in history. This is based on data used on the following website: https://brilliantmaps.com/did-not-vote/ The first activity explains som

This is a detailed description of a "strategy" game anybody who can count up to 100 can play with their class and win each and every time. The rules will take about 45 seconds to describe, and within 3 minutes you will be able to keep an entire class occupied by the question, 'why does he/she/they keep on winning this game?" If you follow the instructions described in this activity, it should easily keep a class engaged, puzzled and frustrated for at least 45 minutes, usually longer. Your class

This is one in a continuing series of activities that takes mathematics and applies it to social issue, including Food Waste and Mathematics: From Farm to Table to Dump, Mathematics, Demographics & Slavery: The 1790 Census in Ratio, Percents & Graphs, MathBusters: Percentage Practice to Analyze 2016 Election Results, and Statistics, Histograms and Lies Presidential Candidates Tell. In this case, we are looking at how far food must travel in order to make it from where it is produced to the place

Here's a very uncomfortable fact: it takes 4 pounds of potatoes to make 1 pound of potato chips. That means that for every 1 pound bag of potato chips you eat, 3 pounds of potatoes have to be thrown away. What a waste of food! This is a series of activities that looks at the hidden world of food waste. It includes a look at how much food is wasted as it is "processed" into finished products like french fries and potato chips. It also includes mathematical activities where students calculate how

This is an investigation where your students design, cut out and fold different networks in order to determine which ones will become a cube. Students are introduced to the concept of a network, learn how it can be used to form different types of polyhedra, and then investigate different ways (there are 11) to create a 2-D net that can be folded into a cube. Students then take the "working" and "non-working" nets and sort them onto a sheet, then compare their properties. There is also an activi

The first U.S. Census was conducted in 1790 to decide on the apportionment of the Congress. The people counted were Free White Males Over !6, who were allowed to vote, White Males Under 16, Free White Females, Enslaved Persons and "Others." Your students will use this data to express relationships between different groups, most significantly the ratio of "Free White Men" to "Enslaved Persons." Please note that this refers to the people who worked as slaves to the current terminology as "Enslaved

This is the most carefully and completely documented use of the "The Handshake Problem" (also known as the "Glass Clink Problem") that you can find. It spans 5 days worth of lessons, homework assignments, enrichment and an assessment. The beauty of the "handshake problem" is that it can be looked at as a way to represent a problem visually through the use of points and connecting edges, but it can be investigated as a sequence of triangular numbers. This is then be compared to other types of seq

Abstract: Zombies are a popular figure in pop culture/entertainment and they are usually portrayed as being brought about through an outbreak or epidemic. Consequently, we model a zombie attack, using biological assumptions based on popular zombie movies. We introduce a basic model for zombie infection, determine equilibria and their stability, and illustrate the outcome with numerical solutions. We then refine the model to introduce a latent period of zombification, whereby humans are infected

From the same wiseguy who brought you "Fractions: You're Teaching It Wrong," "Multiplication: You're Teaching It Wrong (and you really don't have to...), among other deals, I now present unto you, "Division: Take My Word For It, You're Teaching It Wrong." It's 62 pages long! Okay, half of those pages are printable "division facts reminder & practice cards, but still, that's a lot of division for you to digest. 13 concrete techniques that you can implement into your classroom tomorrow, or, even

This is a study guide plus 3 quizzes and answer keys for the article that appeared in the "Ideas" section of the New York Times on Sunday, July 18, 2014. "How Tests Make Us Smarter" Note: the original article can be accessed at this Permalink: http://nyti.ms/1rnx6cC This ideal to be used as a form of professional development. It can be conducted in about 1 hour, including the warm-up questions, discussion, "quiz #1" and wrap up. This is an excellent (and very readable) article about the sc

Here’s the idea: your students need practice converting improper fractions to mixed numbers (and yes, they are “mixed numbers” and not “mixed fractions”), but just doing one of those cruddy worksheets you downloaded off some cruddy worksheet website is just not going to cut it. What if converting improper fractions to mixed fractions could be a little engaging and, dare we say it, fun? Well, games are fun, and a little competition in the classroom never hurt anybody (although it should be emph

I developed this activity for a kindergarten teacher who wanted to introduce her students to the "syntax" and "grammar" of writing equations without the need for drill. She also wanted me to make it somewhat fun, AND include practice for fine motor skills, as well as practice writing numerals. Can you believe it, I packed this all into one activity? Yes, I did, and here it is. Full disclosure: this is NOT a "drill your little kindergartners on addition and subtraction facts." Kindergartners are

ALL KILLER - NO FILLER! This is the all the materials you need to teach a killer, do you hear me, KILLER lesson where students will identify and practice sorting 4 different addition strategies. The strategies: "Count On" "Doubles" "Near Doubles" "Make Ten" What I love about this lesson is that it reviews these 4 strategies without having the teacher name them directly: instead, you place examples of each strategy on separate areas and then ask the students to create more

I know this is growing out of control, and lucky for you, I kept the price at $9.95; consider this a bargain! • Recently added: Why you should NOT make your students draw fractions (they'll stink at it no matter how hard they try), and an excellent alternative to drawing cruddy pies, wobbly bars and squishy squares.... • Complex Fractions: every heard of them? Show this to your kids and they'll develop new strategies for comparing fractions and finding new ones. * I explain why you should never

October 3, 2014: Please note, this is now 87 fun filled pages, and includes everything below with additional activities: Activity: Dude, Where's My Locker? These are 10 different "clue games" about multiples and factors to find a locker. Includes a Do It Yourself sheet so your students can make their own problems and share them. Activity: Let's pick a number - my friend walks into the classroom with a jar of tiles labeled 1 - 100. She is blindfolded and makes the following offer: "If I pick ou