When I think about differentiating in my high school classroom, I have two main worries. First, how will I manage different problems or activities? Second, how will I encourage all my students to work on their problems or activities without being mad that they did or didn't get the same problems as their neighbor. To solve both of those problems, I use a Google Form to differentiate.
The trick is to create separate pages within the Google form. Instead of adding questions, I add page breaks. Then I create questions and check the box (next to the multiple choice answers) that says "Go to page based on answer." If the student gets the answer correct, she gets a harder question. If she gets the question incorrect, she goes to a page that provides a hint or tip and then redirects here to the original question to try again.
When I use this in my classroom, the students are aware that they may be solving different questions than their neighbor, but they don't seem to draw conclusions about the level of difficulty in the questions or even ask why they have different questions. It's almost as if they approach it as if they were assigned random questions from a bank of questions. It works pretty well and creates a seamless way to remediate and enrich.
Here is a video I made about the process:
People often ask if I have a template for this process. I don't. It's a little hard to share a form as a template because what someone needs in the form is different each time. I usually start by drawing the whole thing out on paper so I know exactly how many pages I need and what the sequence of pages will be. If you have questions about this, please feel free to contact me!