There was a question which you had to determine the pH of a solution given the Keq was something of the order 10^-7, and the pH was like 10.smth. To do that q accurately, you had to have the initial concentration of [OH-] in pure water to be 10^-7, otherwise your quadratic is a bit off. I don't...
Everyone who's got experience in oly maths can confirm international maths olympiad is much harder than 4u maths.
4u maths - requires maybe a month or so to get good at
oly maths - years of training required, thousands of hours doing maths
No, what you're saying is you're either choosing any two of the 4 possible spots for one digit (e.g. you're choosing the last two digits to be 1 if your initial 2 digits are 2, 1) and iterating over all possible ordered pairs of numbers, meaning you also count the time you choose the first two...
Of course, I can make mistakes, so any errors found would be great.
EDIT: Newest version now a file on google drive as my last edit caused it to become too large: https://drive.google.com/open?id=1U_buMWY-R6i_ti3HunPg9TbSj_o74zFR