To subitize means to instantly recognize small groups of numbers.
Subitizing should be a regular routine in math classrooms. It takes just a few minutes and the students will love it.
Flash the screen and then quickly move to the next (blank) screen. Have students raise their hands when they know the number show Call on several students and ask for their answer and HOW they knew the number.
23 subitizing cards with 10 and 20 frames