- To find the 10's complement
- Find the 9's complement and add 1
- Subtraction
If the carry out is 0, the sum is negative, take the 10's complement.
Otherwise the result is fine
- Find the 10's complement of
125 => 874 + 1 => 875 Test 125
+875
----
1000 => 000
5298 => 4701 + 1 => 4702 Test 5298
+4702
-----
10000
- Let's try some subtraction
269 269
- 128 => 871+1 => +872
---
1141 => 141
3421 => => 3421
- 4237 5762+1 +5763
-----
9184 => 0815+1 => -816
- With 9's complement if there is a carry, take the 9's complement
- With 10's complement, if there is no carry take the 10's complement