If you add print(entered_code, correct_code), you will be able to see what the inputs are in the console log. You might get a hint from there.

Find the sum of all multiples of n below m

Sum them up and you'll get 256686.

All multiples of 1 below 717 are: 1, 2, 3, ... ,716. Sum them all up and you'll get that number, not 717.

Here, n = 4 and m = 123.
As for the conditions 'm' is exclusive so 'm' is not included incase it is multiple of 'n'
123 isn't a multiple of 4 so our example will contain [ 4, 8, 12, 16, 20, ...., 120 ] as the final set of
all the multiples of 4 smaller than 123. Now just find the answer by adding all the elements i.e. 1860