Subitizing is the ability to looking at objects in different combinations and be able to identify how many without counting it. Subitizing is an important part of constructing number sense. For young kids, one of the best ways to develop subitizing skills is through games. This product provides different combinations of numbers 1-5 through dots and 5 frames.
The way I use this in my classroom is laminating each sheet and then cutting out each card. Afterwards my students get to use their deck with their partner to play games: Make 5, Make 10, Go Fish, War...