1
+   1
=  10

    
+   
=   

    0
+    
=    

     
+   0
=    

    1
+    
=   1

     
+   1
=   1

    0
+   0
=    

    1
+   0
=   1

    0
+   1
=   1

     111
+   1101
=  10100

        11111111
+   100000000001
=   100100000000