A
B
C
D
1
1
2
2
1
0
Half-Adder
A
B
0
Sum
Cry
1
0
3
1
Half-Adder
1
0
A
B
3
0
Sum
Cry
1
Half-Adder
1
0
4
A
B
0
Sum
Cry
4
1
Half-Adder
1
0
A
B
0
Sum
Cry
1
5
5
A
B
C
D