Can I skip the first instruction screen?
How should the feedback sounds be explained to children?
With kids 6-10 you can tell them what the beeps mean (high beep means correct, low beep for incorrect response.) For children 3-5 we find that having beeps on but not mentioning them is better. With kids 6-10, even if the beeps are not mentioned, they don't ask about them. It is set up to sound like the computer saying "I got your answer." Either way (mentioning/ not mentioning) is fine.
What if a child gets all of the practice items wrong? Do I still proceed with the test trials?
Usually, we don't find terrible performance early on. You should make sure the child knows exactly what they are supposed to do. You can tell them everything about the task-including that sometimes the sizes of dots are different, etc. and that they should always answer based on number. The kids generally find this to be very intuitive. Just try to have your instruction finished before trial number 6 or so, and from that point on you can just pepper in, "You are doing great!" and positive comments like that whenever you feel it is necessary. Because it is psychophysics, we want the kids to know exactly what the game is and be comfortable with it. Then, the measure is focused on their internal ability and not on their understanding of what is expected of them. You can give lots of feedback up through the first 1-6 trials (6 isn't a magic number, it is just that by trial 6 any confusions have likely been cleared up.)
Can children manage responding reliably on a laptop keyboard?
Yes. We use a laptop for all of our in person testing.
For the results folders, apart from having a unique, recognizable identifier for each subject, what would be a good organizing principle (age, sex, school, etc.) for the results?
It would be good to retain any info that you think might be a quesiton of interest. e.g., school, sex, etc. Age should be in the output file, but you might like to keep DOB for more precise info. Making long file names is fine and is a good way to keep the info.
Will gender differences that will affect the results of Panamath?
While we have seen some differences in precision and especially precision between boys and girls at older ages, at the moment, any such difference appears to be attributable to factors other than sex (eg. interest in mathematics, self selection for engaging in studies of mathematics, etc).