Khan Academy
Khan Academy: Divisibility Tests: The Why of the 3 Divisibility Rule
Why you can add the digits to see if something is divisible by 3.
Khan Academy
Khan Academy: Divisibility Tests: The Why of the 9 Divisibility Rule
Why you can test divisibility by 9 by just adding the digits.
Art of Problem Solving
Art of Problem Solving: Divisibility Rules for 3 and 9
Watch this video tutorial to learn divisibility rules for 3 and 9. [7:26]
Art of Problem Solving
Art of Problem Solving: Divisibility Rules for 2, 4, 5, and 25
Video tutorial uses examples to reinforce understanding of divisibility rules for 2,4,5, and 25. [6:06]
Loyola University Chicago
Math Flix: Divisibility Rules
This QuickTime movie provides an opportunity to learn and practice the divisibility rules. As you watch and listen to the teacher and student interact it helps clarify the thinking behind applying this concept.
Study Pug
Study Pug: Squares and Square Roots
This video focuses on finding the square of a whole number and the square root of a perfect square. In order to do this, you will first learn how to do prime factorization, a method to find the prime factors of a number. [1:58]
Study Pug
Study Pug: Estimating Square Roots
This video teaches you how to estimate square roots which are not perfect squares without using a calculator. Explanations and examples are included. [3:45]
Sophia Learning
Sophia: Divisibility: Lesson 1
This lesson grouping provides students with a wide variety of tricks and techniques to determine if one number is divisible by another number. It is 1 of 6 in the series titled "Divisibility."
Sophia Learning
Sophia: Divisibility Rules: Lesson 10
This lesson introduces the rules of divisibility. It is 10 of 11 in the series titled "Divisibility Rules."
Sophia Learning
Sophia: Divisibility Rules: Lesson 2
This lesson introduces the rules of divisibility. It is 2 of 11 in the series titled "Divisibility Rules."
Sophia Learning
Sophia: Divisibility Rules: Lesson 7
This lesson introduces the rules of divisibility. It is 7 of 11 in the series titled "Divisibility Rules."
Sophia Learning
Sophia: Millimeters & Centimeters: Lesson 3
This lesson will go through the steps involved in using a ruler to measure length in centimeters and millimeters. It is 3 of 4 in the series titled "Millimeters & Centimeters."
Sophia Learning
Sophia: Millimeters & Centimeters: Lesson 4
This lesson will go through the steps involved in using a ruler to measure length in centimeters and millimeters. It is 4 of 4 in the series titled "Millimeters & Centimeters."
Sophia Learning
Sophia: Millimeters & Centimeters: Lesson 1
This lesson will go through the steps involved in using a ruler to measure length in centimeters and millimeters. It is 1 of 4 in the series titled "Millimeters & Centimeters."
Sophia Learning
Sophia: Multiplying 2 Digit Numbers by 1 Digit Numbers: Lesson 3
This lesson will go through the steps involved in multiplying a two digit number by a 1 digit number. It is 3 of 4 in the series titled "Multiplying 2 Digit Numbers by 1 Digit Numbers."
Sophia Learning
Sophia: Multiplying 2 Digit Numbers by 1 Digit Numbers: Lesson 4
This lesson will go through the steps involved in multiplying a two digit number by a 1 digit number. It is 4 of 4 in the series titled "Multiplying 2 Digit Numbers by 1 Digit Numbers."
Sophia Learning
Sophia: Multiplying 2 Digit Numbers by 1 Digit Numbers: Lesson 1
This lesson will go through the steps involved in multiplying a two digit number by a 1 digit number. It is 1 of 4 in the series titled "Multiplying 2 Digit Numbers by 1 Digit Numbers."
Sophia Learning
Sophia: Zero and Divisibility: Lesson 3
This video discusses the fact that dividing by zero is impossible and so no numbers are divisible by zero. This lesson is 3 of 7 in the series titled "Zero and Divisibility."
Sophia Learning
Sophia: Zero and Divisibility: Lesson 1
This video discusses the fact that dividing by zero is impossible and so no numbers are divisible by zero. This lesson is 1 of 7 in the series titled "Zero and Divisibility."
Sophia Learning
Sophia: Divisibility: Lesson 2
This lesson grouping provides students with a wide variety of tricks and techniques to determine if one number is divisible by another number. It is 2 of 6 in the series titled "Divisibility."
Sophia Learning
Sophia: Multiplying and Dividing by Multiples of 10: Lesson 2
This lesson will demonstrate patterns that emerge when multiplying or dividing by multiples of ten.
