old_contents: num = 4; # will be integer variable
  str = "Hello, String."; # will be string variable
  flnum = 4.0; # will be float num
  print num;
  print str;
  print flnum;
new_contents: num = 4; # will be integer variable
  str = "Hello, String."; # will be string variable
  flnum = 4.0; # will be float num
  print "First condition for variable num:", num;
  print "First condition for variable str:", str;
  print "First condition for variable flnum:", flnum;
  num+=2;
  str+=" Love you";
  flnum-=2.0;
  print "Second condition for variable num:", num;
  print "Second condition for variable str:", str;
  print "Second condition for variable flnum", flnum;
  
subject: add arithmetic ops