0:00:04.069,0:00:10.019 A variable is a container that you can store[br]a value in. When you use that variable in 0:00:10.019,0:00:15.639 an algorithm, it opens up the container and[br]looks at the value inside. This lets you write 0:00:15.639,0:00:20.820 smarter algorithms that behave differently[br]depending on the value stored in the variable. 0:00:20.820,0:00:25.800 Now you're going to try playlab where you[br]are given different games and you can change 0:00:25.800,0:00:31.689 the values of variables like speed, height,[br]score, in order to change the game. You won't 0:00:31.689,0:00:37.020 have to change the algorithm of the game to[br]change how it plays, just the variable. In 0:00:37.020,0:00:41.960 my work for Kindle and on X-ray for books,[br]we apply variables in many different ways. 0:00:41.960,0:00:47.550 One way that you can use a variable is to[br]store page numbers of a book. A user can increase 0:00:47.550,0:00:53.059 and decrease the size of the font on a page.[br]Based on the font size, the number of pages 0:00:53.059,0:00:58.030 in the book can change. We can adjust it by[br]storing the number of pages in the variable.