1. What is the smallest number written exactly with 7 digits?
2. What is the smallest integer using 11 digits i.e. all digits 0 to 9 and an extra digit 2?
3. Write down the smallest square s.t. each digit is present at least once.
4. Evaluate the quadruplet {a,b,c,d} of distinct non-negative integers, s.t. a*b+c+d=2023 and abcd is minimal.
The 1st solver is kindly requested to post at least 2 answers out of the set of four.
Part 1 (spoiler)
