Does a manual computer count? Addition and subtraction were the only things I learned on this Japanese abacus, but it was awesome once I learned. My fingers would automatically work the beads without my having to think through the process. Give my brain a number, and my fingers would add or subtract the beads. I used it for balancing my checkbook.
Note to Self: Never draw something with 115 little beads. My attention span is only good for three beads.