To scan is to read quickly to find specific facts. To skim is to read quickly to get a general idea of the text.

To "scan" means to scrutinize closely looking for something SPECIFIC. A sailor might scan the ocean with a spyglass or binoculars looking for land. Another example is "scanning" an invoice to look for the final price. We can also scan the telephone book looking for a specific name. If we can say, "there it is", we are scanning. To "skim" is get a basic overview or GENERAL idea. Most of us skim over the headlines of the magazine covers on display when we are waiting in line at the grocery store. When we get a new book, we might skim over the chapters to get the gist of how the story will develop. Hope this helps

To scan is read text quickly and pay attention to all details. it focuses on everything carefully. to skim means read quickly and Find general Idea of text. good luck!

Both of them are the techniques for fast reading; in order that you do not waste time. These techniques are used to find specific information and to get a comprehensive conception of the text respectively.