The world of actual programmers is NOT filled with fake programmers. The world of people actively applying for advertised programming positions IS dominated by

The world of actual programmers is NOT filled with fake programmers. The world of people actively applying for advertised programming positions IS dominated by fake programmers. That's why FizzBuzz is an effective screen. As to your last question, a "webdev" who doesn't understand integer modulus is a fake programmer. Is it critical? I suppose it's not if your grid is never wider than one column and you never want to alternatively style rows in a list or table.