No BTDT as a parent, but in my university STEM department, we're about to graduate an undergrad with discalculia, and we've admitted her as a PhD student to do a computational/modeling project. As you observe in your DD, this student grasps the big picture quickly, which is a huge advantage in the field. She's learned to solve problems without numbers, and then she relies on calculators, spreadsheets, or Matlab for the computation.
No game apps, but dice games are great for teaching that level of math facts. If Yahtzee is too obviously math, then any game that involves rolling two dice and using the total will reinforce the addition.
We do have a math facts app that's straight facts that we like because you can control the set you work on to a very small number, and it graphs the results. "Math Drills"
