how to get all the possible combinations for 4 digits from a 5 digit number.
i need a pair that has both 5 digits and four digits. their sum must be equal to a five digit user input.
user input : 14690
14690 has pairs 12345 + 2345
2345 came from 12345
lets say that x = 12345 and y =2345
besides y == x%10000
other formula can i have since if i use % and / i will have a lot of declarations