Sentence:  The text is inscribed on a clay tablet of a very unusual format. The only other known mathematical <WSD>cuneiform</WSD> text on a clay tablet of a similar format is also the only previously known Kassite (and therefore post-Old-Babylonian) mathematical <WSD>cuneiform</WSD> text. 
Meaning of the word marked with <WSD> tags:  Written in the cuneiform writing system.