SamizdatMath

Many, MANY years ago I had a student in a 7th grade math class who was working on some kind of assignment that required solving the problem 25 ÷ 8. He called me over and pointed out that there must be some kind of error in the problem, because 8 does not go into 25. Being the budding klugarsch that I was, I remarked that, in fact, 8 did “go into” 25 (if you mean how many times can you count up by 8s before getting past 25), but that it didn’t do so without leaving a remainder. Which got me thin

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

This is NOT your typical "is this a prime or composite number, and if it is composite, show the prime factor" exercise. No, this is an activity that actually demonstrates how figuring out prime factors is linked to encrypting information securely. If you know about the Russian Postal Service puzzle, then you'll appreciate this. There are 10 different puzzles, and then a "DIY" where your students can make their own "prime puzzlers" to share with one another. If they're really good, send them to

This is the one and only collection of "MadHard" 'puzzlas' that I have been collecting, editing and finally, answering for more than a decade. Each one is designed to test the mathematical meddle of your kids, from 3rd through 8th grade. Are they hard? Oh, some are sooooo hard that they even stumped mathematicians! Others are a little less hard, but they're all pretty unique and fun and the contexts are nothing like you've ever seen before. Here are some examples: • A cute baby dressed as a tac

Think about it: the average American eats over 40 slices of pizza a year; if you live to be 80, and assuming you start at around 5 years old, this is 75 years of pizza x 40 slices per year, or 3,000 slices in your lifetime! Since this delicious food is such an important part of our life, doesn't it make sense that we understand everything there is about the economics of buying pizza? This is a series of activities that examines the economics of pizza in several different ways. First, it shows

Teach your students the importance of ratios and unit rates.

This is the same as Number Logic Puzzles Silly Creatures with a Christmas holiday theme, which should really motivate your students! This is a fun little booklet that your students can put together in about 3 minutes and we’ll really give them some fun working logically - and because this is something you purchased from me, your kids will also have a chance to make their own puzzles to share with one another. Ain’t that cool? Comes in b//w and color booklets - the color booklets have been for

Note: this is the same as the "winter theme three part number logic puzzles," but with "silly icons" instead of "winter icons." This is a sequel to Silly Creatures Number Logic Puzzles, a fun little booklet that your students can put together in about 3 minutes and features 2 kinds of objects to decipher. This version involves three different objects to interpret, which will really give them something fun to do and most likely fry their brains by working logically - and because this is somethin

"On a bad day, I have no ideas. On a good day, I have a lot of wrong ideas. At least with wrong ideas, I can mix them together and come up with a right answer." That's the idea behind this number puzzle, which I've intentionally designed to be really tricky and frustrating (at least, it was for the 3rd through 6th graders I tried it on.) The relationship between the three columns appear to be arbitrary, but there actually is some method to the madness: the students should be encouraged to come

No, it's not a "scoot" game or a tradition "bingo" game; this is an estimation strategy game where students use 4 numbers to create a fraction and then turn it into a decimal (either by hand or using a mental strategy, NOT LONG DIVISION!), round it off (if needed) and then find a square that satisfies that decimal. However, there are many ways to choose a square: some clues are "between" clues ("between .2 and .3") or "exact" clues ("exactly .25") or "less than" clues ("less than .2") which mea

This is a "bingo" style game where players have to get 5 in a row. Sound pretty boring, right? Well, it ain't. Here's why: instead of just being a "one to one" correspondence game where the teacher calls out some bogus fraction (like, uh, 4/5 = ? %), this is a game where students choose from 4 numbers, create a fraction and then convert that into a percent, and then choose whatever square fulfills that percentage. Except the squares are not all exact percentages: most of them are "between 20%

This is a collection of 12 different division reasoning problems that require your students to understanding through written explanations. No, it doesn't mean your students are going to explain the long division algorithm by writing about the steps they took to solve the problem. First of all, who cares? Second of all, it doesn't really show a mastery of the concept of division; it only shows they have memorized the steps in an algorithm that is totally unnecessary to memorize in an age of calcu

This is an activity designed to help our students learn about the importance of rounding off numbers after they have been divided and using them as a basis for comparison. One of the things our students should learn is the importance of rounding numbers to that they are easier to handle and to cite as a statistic. For example, to say "for the same amount of taxpayer money that Donald Trump has spent on golfing vacations to his Mar-a-Lago resort we could have paid for 9041.59132007 Meals on Whee

This is a short activity with specific instructions that deals with the misconception that the decimal point is the "center" of the base ten system. The reality is that the decimal point has two functions, one of which is to act as a "pointer" to the ones place, which is the actual divider of the place value chart. This goes a long way towards explaining to your students why there is no "opposite" of the ones place: it is the actual center from which the decimals and whole numbers originate. Th

This is a fun approach to understanding the importance of ratios and proportions when working with visual arts: I took the famous Gilbert Stuart photo and cropped it so that it would be 2" x 3" and then made enlargements based on adding 1" to both the width and the height. The result is a distorted George that looks like he has had a tooth removed; Seriously, the idea here is that your students look at a series of photos, measure them in inches, and then organize that information into a chart w

Did I ever tell you that I design amazing assessments? Everybody says so: they are the best assessments you've ever seen. The other assessments you've seen? They're a disaster. Sad. This is a percent assessment that is unlike any that you have ever done. First, it requires your students to use scissors! Second, there are very few "clean" numbers (that is, exact numbers) because, well, life is NEVER exact! Third, it assesses on concepts and skill AND problem solving, so your students have to in

Okay, you think this is just one big joke: "Want a Hurtz Donut?" "Sure!" "Ouch!" Promise: hand your students a calculator and this assessment and you'll find out all sorts of things about what your students DON'T know about a concept they learned in 3rd grade: Division! This is a fun and non-threatening away to assess what your students actually know about division without having them do some dumb algorithm which they'll never use for the rest of their lives (except for some assessment cre

A lot of people ask me where I get all the ideas for my materials, which, you’ll have to admit, are rather strange in many ways. When you see math “everywhere” like I do, you’re always thinking about how math “fits in.” I came home from work one day in the mood to make gungjung tteokbokki, and wouldn’t you know, all I had was frozen pork. So I pulled it out of the freezer and stuck it in the microwave on the “defrost” setting (which actually works pretty well.) What I noticed was that I had purc

I know you all love "Task Cards" - so I made these for you, but at the same time, I had to get "snarky." Forgive me..... See all those stoopid questions that show up on Facebook, Instagram, PInterest, Friendster, Tumblr, Twitter, Woof, etc? The ones where they tell you to calculate some easy-peasy problem and then 83% get the wrong answer? Wouldn't that make a great activity for reviewing order of operations, a.k.a. PEMDAS????? So I collected a whole bunch of these, spread them over a few pag

This is a neat little activity that you can do in about 1 - 2 periods to get kids factoring. Excellent for an introduction to prime factorization, or a review, it uses a linear method to break numbers down into prime factors. It also has a nice motivational "warm up," and, like all my materials, funny graphics, riddles, "do it yourself" activities and an answer key. My kids liked doing this activity, so will yours, okay?