If the only factors a number are 1 and itself, then that number is prime. A number that is not prime is called composite. Learn about prime and composite numbers by watching this tutorial!
Prime numbers aren't too hard to define, but they still puzzle professional mathematicians. Believe it or not, all over the word computers are chugging away, trying to find the next biggest prime! Bigger and bigger prime numbers help keep your credit card info safe through really cool encryption techniques. So prime numbers really matter every day, and you can learn how they are defined in this tutorial.
Integers are everywhere in math, so it's important to know what an integer is. This tutorial explains this special type of number so that you can identify one when you see it! Sometimes, a number is an integer even though it doesn't look like one. Watch this tutorial to see how to identify those too!
To find the greatest common factor (GCF) between numbers, take each number and write its prime factorization. Then, identify the factors common to each number and multiply those common factors together. Bam! The GCF! To see an example worked out, check out this tutorial!
To write the prime factorization for a number, it's often useful to use something called a factor tree. Follow along with this tutorial and see how to use a factor tree to find the prime factorization of a given number.