Math Facts and Games

After our last weekend together, I brought back another game for my students to play. It was the finger game where each person places his or her hand behind the back, and both people try to say the sum first. We played it with one hand, then moved into using two hands. They loved it. We refer to it as 1 or 2 hand addition.
We are going back through the games once again. Many seem to be motivated as long as I allow them to add the war element some days. They compete to see who is quicker to recall the sum or difference of the facts.
However, I have four students who struggle with addition and subtraction facts. Why are they so far below the rest of the class? These students have made gains, but they are where the rest of the class started the year. These students came in only scoring 0-2 facts correct per minute on addition and subtraction timed tests. They are up to 11-13 with addition but only about 5 with subtraction. Three of those students are currently served for math and reading interventions and making limited progress. They have been through the problem solving team and are currently being referred for evaluation and special education. I do not know what to do with these three students. I am with them the majority of the day in order to complete anything.
I have decided that they will now work with me in a math group during our math games. I am having them use die and add two of them together between which involve the numbers 1-6. The three students have made strides as in the beginning of the year these students had to touch the numbers on the dice in order to count them. They could not look at them and say that number and were extremely dependent on their fingers for everything. Now, some problems are automatic for them and do not require the use of fingers. Yeah!
What else can I do to help these struggling students? What can I do to motivate them to do better with basic facts?
As for my other students, I have many students who have made tremendous progress since the beginning of the year. This past week, I had a handful of students recall more than 30 addition facts within one minute. Three students were in the upper 30s to low 40s. Amazing! Now, can they maintain it over time?
With the progress I have seen this year, I am continuing my work throughout the rest of the school year. We will work more with subtraction games and activities as I see students need more work in that area. I also am going to allow my more advanced students to work with some games involving multiplication.