Find here free online math videos on division, long division, factors, divisibility, and primes, meant for 3rd, 4th, and 5th grades.
These videos match topics in Math Mammoth Division 1 worktext (Blue Series).
The connection between multiplication and division
Divide evenly into groups — basic concept of division
Division versus multiplication word problems
These videos match topics in Math Mammoth Division 2 worktext (Blue Series).
The order of operations plus writing simple expressions
The remainder, part 2 – we learn to write division with a different symbol and learn about the remainder in word problems
Long division — step-by-step examples (several videos)
Remainder problems – word problems involving long division with a remainder
Find fractional parts with division
These videos match topics in Math Mammoth Multiplication & Division 3 worktext (Blue Series).
Review: Multiplication and Division – simple equations, bar models, terminology
Long division with a two-digit divisor
Long division as continued (repeated) subtraction
These videos match the topics in Math Mammoth Factors & Factoring worktext (Blue Series).
Divisibility (and factors & multiples)
An introduction to prime numbers
Prime factorization using factor trees
The sieve of Eratosthenes (for finding primes)
How to use factoring to simplify fractions, and how to cross cancel