Mathigon
Mathigon: Math Foundations: Divisibility and Primes: Divisibility Rules
There are a few different rules that can make it easy to check if a number is divisible by another. In this lesson you will learn some of them such as,any number that ends in 0, 2, 4, 6, or 8 is divisible by 2, divisibility by 5 we...
Khan Academy
Khan Academy: Factor With the Distributive Property
Practice applying the distributive property to factor numerical expressions (no variables). Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
University of Waterloo (Canada)
University of Waterloo: Cemc: Math Circles: Number Theory Ii [Pdf]
This worksheet provides a series of problem-solving questions that require higher order thinking skills. Questions will include finding the greatest common divisor, and least common multiple.
Other
Sierra College: Elementary Algebra Review Sheet and Common Formulas
This review sheet includes important rules, properties, formulas, and equations needed to solve many Algebra problems.
Khan Academy
Khan Academy: Gcf & Lcm Word Problems
Solve word problems where you either need to find the GCF or LCM. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Other
Help With Fractions: Finding the Least Common Multiple
This website gives an excellent explanation of how to find the least common multiple. It offers two different methods and gives easy to follow step by step directions.
Cuemath
Cuemath: Least Common Multiple
Learn about the properties of Least Common Multiples (LCM) and the three methods to find the LCM. Included are solved examples and interactive problems for review.
Khan Academy
Khan Academy: Prime and Composite Numbers Intro
Discusses factors, prime and composite numbers, and why the number 1 is not prime or composite. Includes practice problems throughout, along with explanations of solutions.
PBS
Pbs Learning Media: Harry the Substitute Teacher
Harry and his students look at various arrangements of classroom desks in this video from Cyberchase.
George Mason University
Margo Mankus: Investigating Lcm and Gcf Using Rods
This lesson plan is for an activity using rods (Cuisenaire Bars) to help students understand the concept of factors, in particular the LCM and GCF of two numbers.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice Problems Number Theory
Practice using your graphing calculator for number theory problems, including prime factorization, greatest common factor, least common multiple, and scientific notation. If you get stumped or if you would like to check your work, then...
Illustrative Mathematics
Illustrative Mathematics: Picturing Factors in Different Orders
The purpose of this task is to help learners picture the multiplicative structure of the number 30 in different ways. Some of this structure is easier to communicate using grouping symbols, as it is easier to interpret...
University of Cambridge
University of Cambridge: Nrich: Making Sticks
On this one page website sharpen your logic, factors, and multiples skills while working on this challenge. The solution is available to double check your solution.
University of Cambridge
University of Cambridge: Nrich: Block Four
On this one page website sharpen your logic, factors, and multiples skills while working on this challenge. The solution is available to double check your solution.
Texas Instruments
Texas Instruments: Oliver's Method
Students discover a relationship between the Greatest Common Factor (GCF) and the Least Common Multiple (LCM) of two numbers. Students will find and justify the relationship that the product of two numbers is equal to the product of the...
Topmarks Online
Topmarks: Multiples and Factors
A multiple-choice game with two game modes. In the first, you need to identify the Lowest Common Multiple and in the second the Highest Common Factor. Questions increase in difficulty depending on accuracy.
Khan Academy
Khan Academy: Greatest Common Factor
Find the greatest common factor of 2 or 3 integers. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Paul Dawkins
Paul's Online Notes: Algebra: Zeroes/roots of Polynomials
Learn about the root or zero of a polynomial with this reference guide. Includes definitions, step-by-step instructions on how to find all the zeroes for a given polynomial, and multiple examples. Also included is a description of The...
Elias Saab
Math Drills: Lcm and Gcd Quiz
An interactive quiz which provides students with two numbers and asks them to find either the Least Common Multiple or the Greatest Common Divisor between them. Students input their solution and have the program evaluate it. Hints are...
Teaching Treasures Publications
Teaching Treasures: Year Eight Nine Math (Page 1)
Review a variety of number sense skills using this interactive worksheet. Concepts include greatest common factor, lowest common multiple, rounding to the nearest thousandth, and determining percent. Answers can be checked immediately...
Alabama Learning Exchange
Alex: My Favorite Number
The activity allows students to review many of the number theory concepts. Students will pick a composite number write verbal expressions about the number, find the factors, prime factorization, list multiples, draw a cartoon character...
CK-12 Foundation
Ck 12: Math Grade 4
Browse resources related to fourth-grade math standards. Click on a topic for interactive lessons, videos, and extra practice.
Other
New York State Education Department: Seventh Grade Math, Book One (2006) [Pdf]
Part one of two; The March 2006 7th grade Math test from the State of New York. The test is 30 multiple-choice questions ranging among topics such as number sense (scientific notation, factors), geometry (shape identification, nets),...
University of Cambridge
University of Cambridge: Nrich: What's Left?
On this one page website sharpen your logic and factor recognition skills while working on this challenge. The solution is available to double check your solution.