You are prohibited from using calculators or programming of any kind to solve this question, feel free to use pen and paper though.

Consider the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Using them you can build the number abcdefghij

in such a way that

a forms a number that is divisible by 1;
ab forms a number that is divisible by 2;
abc forms a number that is divisible by 3;
abcd forms a number that is divisible by 4;
...
abcdefghij forms a number that is divisble by 10;

1) Assuming each letter is a different number, what is the value of abcdefghij?

2) Assuming each letter can assume the same number as other letters, what are the possible values of abcdefghij?