4 bit subtractor circuit not showing correct output

[aliraza786]

i use adder ic to make 4 bit subtractor, i wana subtrac 10 from the input value when it is greater then 9, i put the code of 10 at the 4 pins of adder ic and the ther 4 pins is for input bumber i put the carry in bit high but ic didnt show the correct value,my mean subtraction is not correct...pleas see the digram......any help will be highly appriciated..

 

[barry]

You're trying to do this

1 (CI)
1011
+0101 (1010 inverted)
----------
0001 +CO=1

That looks right to me: 11-10=1