Used in over 1,700 districts.

CCSS Math Standard: 4.OA.4

Gain familiarity with factors and multiples. Find all factor pairs for a whole number in the range 1-100. Recognize that a whole number is a multiple of each of its factors. Determine whether a given whole number in the range 1-100 is a multiple of a given one-digit number. Determine whether a given whole number in the range 1-100 is prime or composite.

Contig
Contig
Roll three dice and combine them using any mathematical operation. But be strategic to maximize your points!
Gr 3-7
Factors and Codes: First Names (Episode 2)
Factors and Codes: First Names (Episode 2)
Scrambled up somewhere in 161,000 is a first name. Can you find it!?
Gr 4
Factors and Codes (Episode 1)
Factors and Codes (Episode 1)
Let’s use factors to encode and decode words.
Gr 4
Fizz Buzz: A Counting and Divisibility Game
Fizz Buzz: A Counting and Divisibility Game
Ready for a tricky counting and divisibility game?
Gr 3-6
Game: Number Scrabble
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!
Gr 1-6
Math Curiosity: Klauber’s Triangle
Math Curiosity: Klauber’s Triangle
In 1932, a leading authority on rattlesnakes, Laurence Klauber, discovered a startling pattern within a triangle of primes.
Gr 2-8
Math Curiosity: Ulam Spiral
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!
Gr 1-4
Math Curiosity: Goldbach’s Conjecture
Math Curiosity: Goldbach’s Conjecture
Can any even number be written as the sum of two primes? Goldbach thought so, but we haven’t proven it… yet!
Gr 1-5
Why Is Our Calendar So Weird!?
Why Is Our Calendar So Weird!?
Why are there 12 months? Why don’t weeks fit into months evenly? Why don’t weeks fit into the year evenly? What’s going on with the calendar!
Gr 3-4
Math Curiosity: Primes and Squares
Math Curiosity: Primes and Squares
Can any perfect square be written as the sum of two primes?
Gr 2-4
Math Curiosity: Legendre’s Conjecture
Math Curiosity: Legendre’s Conjecture
It seems like there’s always a prime number between two perfect squares… but is this always the case!?
Gr 3-6
Math Curiosity: Finding Primes
Math Curiosity: Finding Primes
Prime numbers are unpredictable! How can we possibly find them all? An Ancient Greek mathematician found one way!
Gr 1, 2, 3, 4, 6
Math Curiosity: Twin Primes
Math Curiosity: Twin Primes
What do you call two prime numbers who are very close together?
Gr 3-5