Didn’t even open the link probably

That’s a fair point, I guess I used binary numbers so much i uni that I just know the small ones by heart and that’s why I find it easier. Following the example, I never convert 101 as 4+0+1, I just see it and know it’s 5.

Read, write, and execute are represented by the numbers 4, 2, and 1, respectively, and you add them together to get the permission

Maybe I’m the weird one here but this seems like a counter intuitive way to remeber/explain it. Each octal digit in the three digit number is actually just 3 binary digits ( 3 bit flags) in order of rwx. For example read and execute would be 101 -> 5.