Broken Calculator: Multiplication Cross Product

Broken Calculator: 2-Digit Addition

Adding and Subtracting Fruit

Use super cute fruit to introduce algebraic thinking to your young math students.

Factors and Codes (Episode 1)

Let’s use factors to encode and decode words.

Math Curiosity: Magic Triangles

Can you make each side of this triangle add up to 9 using the digits 1-6?

How Many Will There Be? Chip Off The Block

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Earthworm

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Courtyard

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Checkerboard

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Crosses

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Squares in Squares

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Pyramids

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Sliced Circles

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Xs and Os

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Desks

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Stairs

Give kids a taste of a sequence, let them build an understanding, and then see how far their predictions can take them.

How Many Will There Be? Flowers

These flowers sure are getting bigger faster! How large will they be in step 10? What about step 50?

Game: Number Scrabble

What if we played Tic-Tac-Toe with numbers and instead of three-in-a-row, we add up to 15? Well… then we’d have Number Scrabble!

How Many Will There Be? Triangles Within Triangles

A triangle splits and splits and splits again. How many will there be in step 20?

Math Curiosity: Klauber’s Triangle

In 1932, a leading authority on rattlesnakes, Laurence Klauber, discovered a startling pattern within a triangle of primes.

Math Curiosity: Ulam Spiral

What if we make a huge spiral of numbers and then highlight only the primes? Well, a bunch of weird patterns show up!

Math Curiosity: A Pattern Packed Triangle

Pascal’s pattern-packed triangle is a potent puzzle for pupils to ponder.

Create Your Own Operation

The commutative and associative properties are a whole lot more interesting when you apply them to a mathematical operation that you created!

Parentheses: How big of a change can they make!?

Two tiny parentheses. One expression. How big of a change can they make? Bigger than you think.

How Many Ways: Times Equals Minus

How many different ways can you make this math statement true using only the digits one through nine?

Exponents – How Low Can They Go?

Using exponent patterns, can students predict what the 0th power will be?

Calculators, Patterns, and Multiplying By Decimals

Before teaching students the procedure for multiplying with decimals, how much can they intuitively glean from a structured play session with calculators?

Rounding Numbers (But Not To 10)

What could we possibly do to make rounding more interesting for students who already get it? In this series, students consider how they might round to values other than “the nearest 10.” How, for example, do we round to the nearest 9? 7? 15?

Math Curiosity: Four Squares

Every positive integer can be written as the sum of (at most) four perfect squares!

Math Curiosity: Magic Squares

Imagine a 3×3 square in which every row, column, and diagonal have the same sum. That’s a magic square!

Place Value (Beyond Base 10)

Place value is something we cover in elementary school. It seems simple, but I’d wager that very few adults really understand the topic. I sure didn’t until I worked with non-base-10 number systems in college. Your students can get a taste of this mind-boggling experience by imagining what it would be like if we didn’t have the number 9. What would each digit represent then?

Math Curiosity: Odds & Squares

Why does the sum of the first 5 odds also equal 5 squared?

Doubling Dollars

Say you have a dollar. Say you can double that dollar each day: $1, $2, $4, and so on. How long will it take to reach… one million dollars? Not as long as you might think!

Math Curiosity: Primes and Squares

Can any perfect square be written as the sum of two primes?

Math Curiosity: Twin Primes

What do you call two prime numbers who are very close together?

Math Curiosity: Palindromic Number Conjecture

Using this one weird trick, it seems that you can turn any number into a palindrome!

The Game of 100

Who can get to 100 first in this simple, but delightful, math game?

Math Curiosity: Collatz Conjecture

The Collatz Conjecture: start with any number and get to 1 using just two rules. It seems to always work…