There's no geometric complement in my mind. At times it's useful to think of "wholeness" base 10, so 4 and 6 fit together, and when adding numbers, I sometimes

There's no geometric complement in my mind. At times it's useful to think of "wholeness" base 10, so 4 and 6 fit together, and when adding numbers, I sometimes find the nearest multiple of 10 and then go lower from there. I don't picture numbers in the abstract (e.g. 178); when they refer to something else (e.g. 2 coins), they're a description or a property.