- I am not sure if this question was asked before, but I without surprise am stuck at it again:
![1644232852375.png](/data/attachments/34/34887-faf8165cadd7ce2ec37ce0bdd8b2505b.jpg)
started by defining the four digit number as 1000x + 100y + 10z + u for x,y,z and u being some arbitrary integers set - but I am stuck after this (thanks for the help in advance!!!)