After teaching my unit on fractions, I move on into teaching decimals. It just makes sense because they are both used to represent parts of a whole. Plus 5/10 and 0.5 mean the same thing so it helps kids to start decimals while they are still in the fraction frame of mind.
Check out my PowerPoint presentation at my TpT store.
I spend a week on decimals. The first day I introduce the concepts of decimals by relating them to fractions. I use a graphic organizer to help kids grasp the concept and several other activities, which you can check out at my TpT store.
The next day we watch the following video:
Then we review the graphic organizer with more examples. Next I allow them to show me what they know with a worksheet or matching game.
The rest of the week is spent on adding and subtracting fractions. Here is a video that my kids really love and it helps them understand the most important thing when adding or subtracting decimals.