I understand the concept. I can't do the sum IYSWIM. Same with fractions. It's the actual calculations. It's probably wrong of me to say I don't understand percentages in terms of knowing what they represent., I don't understand how to work out what 25% of say, 75 would be.
I understand that if I have a whole cake and cut it into four, I will have four quarters. But if you ask me what one quarter of 75 is, I couldn't tell you. The bit I don't get is how to work it out, which was always my problem.
I'm better with whole numbers, so I could tell you what half of 100 is without too much thought. I'd have to sit down and work.out half of 75, though.
Like I said an a reply to another PP, I can't subitise, I have to physically count. There doesn't seem to be any sort of connection to numbers in my brain like there is with words. When asked to spell a word, it appears as an image in my brain. I 'see' the letters slot into place.
The best way I can explain it, which is imperfect because I don't know how people who can do this actually do it is that I can't see it in my head.
I can't see how the sum should look. It's like a sort of blindness.
I'm rubbish at explaining all this, sorry, but it's like an empty space where numbers ought to be and they just... aren't.