In Bühler's Palaeography, table IX, I find one specimen for the numeral sign 600 (clearly built on the signs for 100 and 6). I'd be grateful for reference to (and images of) other specimens of 600, especially such as might less clearly be built on the signs 100 and 6. Specimens of signs for 1000 are also welcome.
All of this in an effort to understand how the attached clipping could mean 1000+600 = 1600, which is contextually what it has to mean. (I have less trouble with 1000 than with 600.)