Which exam board are you with for maths? Are you doing foundation tier or higher tier?
higher edexcel ive checked it ranges from 52-40 it did go down to 38 in 2022 and then 47 in 2023 who knows what itll be it seems very light though. im guessing it depends on how everyone does
Well, it depends more on how easy/hard the paper is, which isn't quite the same thing as "how everyone does".
The theory is that if students get slightly higher marks because they put out a paper which is a little easier than normal (not intentionally, just because it's impossible to create two papers of identical difficulty), then they'd adjust the grade boundaries up to compensate. However, if students did better because that year was full of smart kids who studied hard, then they'd leave the grade boundaries alone and students would get better grades.