Why the code below produces in JStudio a number with 3 digits? It really does.

Question

Random Gen = new Random();
int numerKarty = 0;
for (int i=0; i<=4; i++){
int nextNumber = Gen.nextInt(8)+1;
numerKarty+=nextNumber*(10^i);
}
System.out.println(numerKarty);

Answer 1

Because your math will produce a final number anywhere in the range of 52-416
That is your random number in the range of 1-8 * 10^i where i is 0-4 and each successive result of the xor will be
10^0 = 10
10^1 = 11
10^2 = 8
10^3 = 9
10^4 = 14
With all random numbers being the lowest possible value of 1 you get;
10+11+8+9+14 = 52
With all random values being the highest possible value of 8 you get;
80+88+64+72+112 = 416
Or
52 * 8 = 416
Giving you a possible range of any number from 52 to 416