I just wanted to comment that DS's math disability presents like this. He is enrolled in school and gets a lot of help from both his math teacher and the intervention specialist. The IS has worked with DS long enough to understand how his disability presents. But the math teacher still doesn't quite get it, I think. Because DS can follow the directions for that day's work and can seem to understand it -- mostly and with some difficulty, but he can complete the assignments. So it seems like he is progressing and understanding.
However, he forgets everything that is not continually practiced. And by late elementary and middle school, early math concepts are not practiced in the curriculum any more, because it is assumed the kids have mastered them. But for DS, the foundation is not there; it has faded away.
So it seems like he is understanding the lesson of the day, but it is like building a tower of blocks on top of a stack of toothpicks. The foundation is shaky and just crumbles away, and the new material does not ever solidify into true understanding.
DS bombs standardized testing in math. Completely. I can see math getting harder for him each year.
It's a different math disability than someone who has trouble remembering math facts (I have one child like that, as well) or mental math. It's a different shade of dyscalculia. It's not about number sense but about understanding concepts.
DD struggles with all areas of issue: memorizing math facts, mental math, number sense and retaining anything long term. Talk about a long, slow slog up a steep hill in a blizzard wearing cement galoshes. LOL
All of those things make this process much harder but the hardest may be how rapidly something seemingly learned would just disappear again. It took a while for me to realize that just because, in that moment, DD seemed to be grasping something and doing well with it, that didn't mean that the next time we did it she would have any recall at all. It was a very frustrating, demoralizing experience for both of us. It felt like every time we seemed to make progress we would end up back at square one. Not even square one, actually. We would lost ground because DD would get so down that something she thought she knew was no longer available to her. It was if the knowledge had been surgically removed from her brain. Why keep trying if after tremendous effort and time spent, the information would simply be gone? We did finally find ways that worked better and things are sticking. We just have to do a LOT, I mean a LOT, of review of everything. To keep her from being overwhelmed and not having to do 8-10 hours of math every day (she is usually overloaded after an hour), I had to get clever with built in review (thanks to Math on the Level I found a wonderful way to keep track and keep various concepts/algorithms woven into our day without overwhelming her).
Measuring to the quarter inch is an example of how things would just disappear. Well, measuring of any kind would just not stick. We worked for years to reach a point where measuring of any kind actually computed but even when it would click and she would do it correctly for a week or two, if we stopped reviewing, boom that information would be gone. She would stare at the ruler or the measuring cup or the thermometer and have literally no idea how to measure. Since I find measuring rather useful in daily life (certainly far more useful and needed than Algebra) we kept at it (short lessons alongside her normal math) but I realized that we had to incorporate it into our daily lives DAILY. She now can measure to the quarter inch with a ruler even if she hasn't done it in a few weeks and does well with a measuring cup and mostly can read a thermometer fairly accurately. She cannot measure to the eighth inch without some help but, hey, I'm happy we got to the quarter inch. It just took daily short lessons over years for it to finally click and stick with any longevity.
Unfortunately, most tutors/teachers are not going to understand that this level of constant review could possibly be needed or believe that level of struggle with retention could even exist in an apparently bright child.
Frankly, in ALL math DD needs lots and lots and lots of review or the connections, which are very weak, never solidify at all. The one exception seems to be certain Geometry concepts. Geometry clicks in her brain far better than other areas of math. She needs a lot of review for the terms to mean something when she reads the words but the concepts click better. For the rest? Years, literally years, of review of basics alongside more advanced concepts is the only way she progresses. This is one reason, despite all the built in review in CLE, I also run the Key to Series with DD for fractions and decimals and percents, she still does math fact practice even as she uses a math chart or skip counting or a calculator for learning new material, and we tackle things from different angles all the time. She needs targeted, focused, continual review in areas of extreme struggle and frequently needs those things daily while we also move forward with new material. Even a week off and boom, the information fades away. Slowly, over years, things are sticking long term and don't need as much review thankfully. DD has a lot of confidence in her abilities in math, now. She just knows she is on a MUCH slower time table than an NT kid and she knows she needs a lot more review and a lot more TIME for things to stick.