I don't know if my answer is the best but I can give you what I did during that phase.
IE. spelling bus on the fridge but in the wrong order. I would praise her effort and say great job as I put them in the proper order so she visually sees the correct word spelling.
IE. 17 instead of 7. My response would be "Yes, 7 8 9, etc."
I don't see this as correcting because you aren't saying NO, basically you are acknowledging her trying but providing the right answer.
With numbers, DD would do something similar to what you described when she was younger. I think it is due to rote memorization at that point. She was always skipping over some random number; usually 7 or 9. But I would recite it back to her, making sure to highlight the missed number but always encouraging her; it wasn't long before she had the rote memorization down. Once they get beyond rote memorization and see it as representation of something more the mixing up of numbers and/or dropping of numbers tends to go away. At least that is how DD progressed.
