Deborah - I dont know the numnber of slaves that Carter had, however I met a descendent of one; while serving aboard USS F D Roosevelt (CVA-15). As it happened:
We were on deployment operating in the Mediterranean
during 1964. I received a letter addressed to me
William C. Braxton. When I opened and read part, I
realized that it could not have been written to me. I called
the post office to determine whether there was another William C. Braxton assigned aboard - and was told that
there was and he was attached to one of the aircraft squadrons that was temporarily attached aboard for the deployment. I called the squadron office, and the person answered by identifying himself as: "Braxton speaking".
I asked if his name was William C. Braxton. He answered affirmative and I told him that my name was also William C. Braxton, and that I had just received a letter that could not have been intended for me. I asked him to come down to the supply office; that I wanted to meet and give him the letter. During our conversation, I asked if he knew the beginning of his Braxton name. He replied "yes" and that his GGGG-GFather was a slave of Carter Braxton.