File Types and Extensions
It’s important to know what type of program was used to make the files on your computer. Sometimes, you’ll get an attachment on your email that you can’t open. That might be because you don’t have the program on your computer that the file was made with. For example: if I send you a picture I created using Kid Pix, but you don’t have Kid Pix installed on your computer, then you won’t be able to open the picture I created. Knowing file types gives you more choice in opening files with other programs.
You can tell what type of file it is by looking at the extension. There are literally hundreds of file types out there and they are all identified by the extension. The extension is the three letters you see after the period (or dot) in the name of a file. For example: Word documents usually end in .doc, excel documents will end with .xls. These extensions also tell the computer how to open the file. Sometimes when you leave off the extension while saving a document it won’t open the next time you try.
Here is a list of some commonly used file types and extensions:
word documents .doc
spreadsheets .xls
presentations .pps or .ppt
adobe acrobat files .pdf (reserved for published material)
picture files .jpg or .gif
