My string answers work but my numeric answers come up wrong when typed correctly, what's happening?

var correct = 0; var incorrect = 0;

var QnA = [ ['What is the color of the sky?', 'blue'], ['How many states are there in the United States of America?', 50], ['What is four multiplied by four?', 16] ];

for (var i = 0; i <= 2; i++) { var ans = prompt(QnA[i][0]); if (ans === QnA[i][1]) { correct++; } else { incorrect++; } if (i === 2) { document.write('You got ' + correct + ' question(s) right.<br>'); document.write('You got ' + incorrect + ' question(s) wrong.'); } }

So the first question with the answer blue works but when doing the 50 and 16, it comes up as wrong. I changed the first answer to 4 and then that started coming up wrong but then I changed 50 and 16 to fifty and sixteen and it started working. I don't understand why strings are allowed yet numbers aren't being communicated properly. I've been looking at this for awhile so maybe I'm missing something.