 In England, we call it factorising. In America, it's factoring. They mean to put an expression into brackets. We say it has been factorised. Let's discover what that means and how we do it. Numbers have factors. Expressions can also have factors like this and like this. Factorising is the process of finding the factors. It's a form of simplifying, and basically just means to put into brackets. Then, if we multiplied our factors together, we'd get back to 6x minus 12. Factorising is just the opposite of expanding brackets. Expanding gets rid of the brackets. Factorising puts into brackets. To factorise, we look for the highest common factor of every part of the expression, which was 3 in this example. So let's have a look at another example. What is the highest common factor of 12x? And negative 8. 2 goes into both, but it's not the highest. We want the highest common factor, which is 4. So take the 4 outside of the bracket, as that's the highest factor. Then what do we need to multiply 4 by to get 12x? 3x, so 3x inside the bracket. And what do we need to multiply 4 by to get negative 8? Negative 2, so that also goes inside the bracket. This is the factorised expression. So what about this example? What's the highest common factor of 6y squared and also 12y? So start with the numbers. What's the highest common factor of 6 and 12? 6, so 6 goes outside the brackets. Now, what's the highest common factor of y squared and y? y, so y outside the bracket. What do we need to multiply 6y by to get 6y squared? Just y, so put that inside the bracket. And what do we need to multiply 6y by to get 12y? 2, so plus 2 inside the bracket. It's really important to check our answer, so just expand the bracket to double check ourselves. However big the initial expression, we just look for a common factor across everything and then do the same thing. Here's some for you to do. Pause the video, factorise the expressions and click play when you're ready. How did you get on? So we've now discovered how to factorise into a single bracket. We can also factorise into two brackets, three and many more. We'll discover how to factorise into two brackets in another video and also something called the difference of two squares.