This (simplified) piece of code seems to work:
int OriginalNum;
int AnswerNum;
cout << "Insert your number: ";
cin >> OriginalNum;
AnswerNum = 201*OriginalNum;
cout << "The answer is:";
cout << AnswerNum;
If I copy what visible in your screen, the compiler complains about the variable OriginalNum not being declared. Try to paste my code and see if you have any issue.
Note: the expression OriginalNum*2*100 + OriginalNum is simply a multiplication by 201!
In fact, you have
[tex]x\mapsto 2x \mapsto 2x\cdot 100 = 200x \mapsto 200x+x = 201x[/tex]