Flash is blocked by Chrome as it is considered vulnerable in the security world. But some classes still use programs that require students to allow Flash content - if you try to run the program, you'll get a message that Flash needs to be installed.
In Chrome, you can add specific web sites that allow Flash content. For example, you might have a Chemistry course that requires you to go to a site called www.saplinglearning.com but since Flash is blocked, you're not able to view content or do the required problems.
On Windows or Mac, you might see a message like this or something similar:
When you see this, you may need to change your site settings to allow Flash
- To the left of the web address, click Lock
or Info 
.
- At the bottom, click Site Settings.
- In the new tab, to the right of "Flash," click Allow.
- Go back to the site and reload the page.
You should now be able to run Flash content on this site in Chrome.