Stumped/frustrated.

I’m a first year teacher and was told that at some point this would happen. Today was the day. I spent over an hour on a 5th grade math lesson in which we covered three problems. The lesson was on the “guess and check” method of solving word problems. I explained the process in every possible way I can think of. At the end of the lesson, four of my students were still completely oblivious. What do you do when a few students simply do not get a concept no matter what you try? I could see lightbulbs popping up all over the room during the lesson, but these four never made an ounce of progress.