here we are taking as hex
b+d =bd
where b is one point and d is 2nd point, result should be bd point in concatenation
for your easy dec result will be 189 not 1113
I guess you do understand that this concatenation you're doing is
not point addition but rather a different operation (which makes me feel better), so now you're looking for math properties of this concatenation thing?
Well for starters the operation you're doing is equal to a*len(b)*4 + b [there are 4 bits in a hex char] in terms of the real addition so so you should be able to use it almost anywhere you need an
Ax + B style expression.