RedDeerGuy’s advice at the top is best, and I think everyone else is in agreement.
Go in with a clean slate. Do not try to fake anything. People with learning abilities are of above average intelligence—that is how they are detected, because there is such a gap between their intelligence and their performance. So don’t ‘play dumb’.
The brain doesn’t process all the information in tackling a problem, usually because of perceptual problems or other interference.
On my test, I did not even SEE (register) parts of a math problem and calculated incorrectly, even though I knew how to do the math problems. My overall I.Q. is 148. The part of my brain that calculates, organizes etc etc was only like 40 or 40%. Such gaps are called a Depressed score and are what indicates a learning disability.
One warning: There are psychologists who may be licensed and supposed to be qualified but do not really understand learning disabilities. One I went to used by various government agencies actually thought that a depressed score meant a person was ‘depressed’ and that was the source of their inability to perform academically. Also, his calculating my dyscalculia into the other two areas on he came up with an I.Q. score of only 99, and determined that I was not intelligent enough to be doing the graduate-level work I was doing. That I didn’t have a learning disability but was only of average intelligence and not bright enough to be in grad school.
Fortunately the University’s own psychology department had better evaluators who correctly diagnosed my math disability—and were able to cogently explain how this affected other areas as well using test results