# Prime Factors, HCF, LCM

This applet is a calculator for breaking numbers into their prime factors, and also investigates how to find the HCF (or GCD) and LCM of two numbers.

###### Author and programmer: Ron Barrow

UK Years 7-11, KS3, KS4, Foundation and Higher GCSE - Number

US Grade 6, Grade 7, Grade 8 - Pre-Algebra

Instructions below See also: Number Factors Prime numbers - the Sieve of Eratosthenes PRINT

## How to Use this Applet

With this applet you can investigate prime factors of integers (whole numbers) and also the **HCF** (Highest Common Factor), and the **LCM** (Least or Lowest Common Multiple) of two numbers. You can also see how these things relate to each other, and get a fascinating insight into the behaviour of larger numbers. [NB.The HCF is sometimes called the GCD (greatest common divisor).]

You can get the two numbers in two ways: **either** by entering them in the text boxes at the bottom of the page; **or** by using the random button at the top of the page - you can choose the maximum number of digits in the random numbers by entering a number from 1 to 7 in the "digits" box at the top of the page.

Play around. There's a great deal to learn about numbers from this applet.