Adding and subtracting using actual objects laid out in these 10 frames helps deepen their conceptual understanding of addition and subtraction while developing a better sense of the meaning of numbers and place value.
For example, a lot of kids say 12 when they mean 20. These type of activities reinforce what numbers actually mean. And if you play it with a fun snack like fruit loops, subtraction really gets fun!
In this picture, I was tutoring a 3rd grade kid who was struggling with understanding the quick trick of adding and subtracting nines. It wasn't clicking when he just looked at the numbers, but it was cool to see it click as we took it from the abstract to the concrete with these 10 frames. He quickly got to where he could just imagine the subtraction problem by looking at the 10 frames and reasoning out loud, without using the manipulative.