What is the difference between these if statements?

What is the diffrence between these condition?

if ((middleOfTabIndicator < index * tabIndicatorWidth)) {
                if (index - 1 != featuredTabIndex) {
                 //do something
                }
              }

vs

if ((middleOfTabIndicator < index * tabIndicatorWidth) && ((index - 1) != featuredTabIndex)) {
                //do something
              }

All my variables are int. Aren't these conditions the same? When I write the first condition everything is OK but when I write the second condition the result changes. Why this happens?