Once upon a time. . .
Some of us can still remember the time without mobile phones. To make calls when you weren't home, you could go to a phone booth. Since these telephone boxes are no longer really needed, you can no longer see them often.
We still have one here in Camolin, but there's no phone in it anymore.
The cache is at the provided coordinates and you will easily see it.
To open the case, you have to solve this little puzzle before:
Leon forgot the PIN on his SIM card. Fortunately, he still has a note with the following clues:
B + 2 = D
A - C = C
C x B = A
A / B = D
The PIN is ABCD. Crack the PIN!
Please make sure to leve the place on the way you foud!