"I Walk the Line"
I also use a number line--a large one either on the wall or projected on wall.
I call each student up and have them use a pointer. The child stands directly in front of and points to zero. If the operation sign is "+", the child does a 90 degree turn so he or she is facing RIGHT. If the second number is a positive number, he/she walks forward, counting and pointing to #'s on the line as he she counts. If the second # is a "-", the child walks backward. (For 2 + 3)--face zero, turn right, put pointer on 2, walk FORWARD-moving the pointer and counting, landing on 5. For 2 + (-3). Face zero, turn right, put pointer on 2, walk BACKWARDS-moving the pointer and counting, landing on (-1).
If the operation sign is (-), the child does a 90 degree turn so that he/she is facing LEFT. The other steps are the same. For 2-3, point to zero, turn left, put pointer on 2, walk forward, landing on -1. For
2-(-3), face zero, turn left, put pointer on 2, walk BACKWARD and count, landing on 5. After several students have walked the line, I give everyone a number line to have, and they walk at the same time another is at the board.
This is much easier to comprehend than "the rules". The steps are the same if the first number is a negative.