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Can you recognize the prime numbers in this group of numbers? Which are prime, composite, or neither?

Prime numbers are numbers that have only 2 factors: 1 and themselves. For example, the first 5 prime numbers are 2, 3, 5, 7, and 11. By contrast, numbers with more than 2 factors are call …

Prime/Composite numbers exist because factors exist. Every number has a unique set of factors, and how many factors a number has determines if it's prime/composite!

This video explains the concept of prime numbers and how to find the prime factorization of a number using a factorization tree. It also shows how to write the prime factorization using …

Let's get introduced to Euclid's division algorithm to find the HCF (Highest common factor) of two numbers. Let's learn how to apply it over here and learn why it works in a separate video.

You wouldn't (for small ranges). The problem is the amount of memory you'd need to hold a list of primes for massive numbers (500 digits for example), it's not possible.

First off, all numbers have factors even if it is the number times 1. So if you have x^2 + 6x + 5, 5 is prime, but 5*1=5 and 5+1=6, so you can factor (x+5) (x+1). You also have to remember that …

Sal finds the factors of 120.

You need to keep factoring until you get the prime factors of the numbers, so you can easily find the gcf of various numbers.