program z1000;
var a,b:integer;
begin
  write('Vvedite a b: ');
  read(a,b);
  write('a+b= ',a+b);
end.

Why 'Wrong answer 1' ?

Output only number:
writeln(a+b);

Just add two numbers using + arithmetic operator and print it on screen. No need to print extra string 'a+b= '. Hope it helps.
http://www.techcrashcourse.com/2014/10/c-program-add-two-numbers.html
http://www.techcrashcourse.com/2015/05/c-programming-language-operators.html
http://www.techcrashcourse.com/2015/05/c-programming-language-tutorial.html

Mr. Aman, please don't post working code or links to working code too. Also your account without any submitted code but with links to above site is very strange.