You need to pass it as an extra:
String easyPuzzle = "630208010200050089109060030"+
"008006050000187000060500900"+
"09007010681002000502003097";
Intent i = new Intent(this, ToClass.class);
i.putExtra("epuzzle", easyPuzzle);
startActivity(i);
Then extract it from your new activity like this:
Intent intent = getIntent();
String easyPuzzle = intent.getExtras().getString("epuzzle");
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