How to Sign "Add"
To sign 'add', hold your non-dominant hand in front of your chest in a flattened 'O' shape, with the fingertips pointing down. Start with your dominant hand slightly below it, fingers spread open and pointing up. Move your dominant hand upward to meet the non-dominant hand. As it moves, pinch the fingers and thumb of your dominant hand together into a flattened 'O' shape, touching the fingertips of both hands together.