I used to think that DD4 had major visual-spacial deficits. She has never done a jigsaw puzzle to my knowledge. She also had a very quirky way she went about learning to read. But, she does seem to have a facility for numbers--nothing crazy but it is very innate, so who knows. My point is, I would not jump to any conclusions just yet. Your DD might soon take off in this area.
I think your DD is young, and if she needs help visualizing then that is the place to start. I think you know you are not doing her any favors by letting her get frustrated with math that is too hard for her. I would even take a step back if she was having to use her fingers, etc.
I have never seen dream box. I am not sure what level this type of question is supposed to be. But, to me, It is not about being able to count fingers or count down mentally. It is about recognizing number bonds--that 3,6,9 have multiple relationships. I think it is about solidifying what the student should have learned previously. This foundation is most important. These addition and subtraction facts should become so concrete or have been so innate from the beginning that these types of questions are easy.
How would she do orally? My DD has never seen a written math problem like that, but when I asked her "what plus three equals nine," she knew it almost immediately.
When I asked her a harder one, she did not. So, I think it goes to show it just takes practice and/or development.
Can you find a program that is more visual? Or knock her back where she can "see" the problem? Otherwise, I really recommend cuisenaire rods. I don't even try to teach with them other than having given them the names--just letting DD play with them has helped her tremendously I think. For me, math at this age is about developing number sense.
