 In this video, we're going to discover some key sequence terminology and how to recognise and generate some important sequences. We will come across all of these key sequences and these key words. Each number in the sequence is called a term. This is the first term, second term and so on. This just tells us that the sequence carries on forever. This sequence is very easy to carry on. We can easily spot it's going up by three each time. Because it's plus three every time, we say it has a common difference of three. Sequences that have a common difference, so the same difference every time are called arithmetic sequences or linear sequences. Can you find the next three terms of this sequence? Did you get 21, 28 and 36? These are the triangular numbers or the triangular number sequence. The sequence comes from the pattern of dots needed to make a triangle. They don't have a common difference. The difference changes each time. You add two, then you add three, then four, then five. Square numbers and cube numbers are also special sequences. But what about this special sequence? Can you find the next three terms? Did you get 13, 21 and 34? This is called the Fibonacci sequence. You just add up the two numbers before to get the next term. There's a lot you can discover about Fibonacci, such as if you make squares of Fibonacci sizes, you get a spiral. It's also linked to the golden ratio and is seen throughout nature. This is a quadratic sequence. If we look at the difference, it isn't the same. But if we look at the second difference, it is the same, which means it's a quadratic. Now on to our final sequence. Can you find the next three terms? This is called a geometric sequence. We multiply by the same value each time. We call it a common ratio. So in arithmetic or linear sequences, it's called a common difference. But in geometric sequences, it's called a common ratio. Here are some sequences. Find the missing terms of each sequence and then label what type of sequence it is. Pause the video, answer the questions and click play when you're ready. How did you get on? So now we know the differences between these sequences and what these key words mean. In future videos, we'll discover how to find the general rule for arithmetic sequences, which is also known as finding the nth term. If you've got any questions, comment below. Please like and share our videos. If you liked the video, give it a thumbs up and don't forget to subscribe. Comment below if you have any questions. Why not check out our Fusco app as well. Until next time.