Changing array values $arr = array( "Red ", "Green ", "Blue" ); echo( $arr[0] . $arr[1] . $arr[2] . "" ); $arr[0] = 44; $arr[1] = 12.5; $arr[2] = $arr[0] + $arr[1]; echo( "$arr[0] + $arr[1] = $arr[2]" ); ?>