This is true. Its also true that most sentient animals can't transform corpuses of ASCII text into somewhat novel, syntactically correct and topical responses to a prompt. So some degree of facility with wordplay and math clearly isn't necessary for sentience.

Is it sufficient though? I think that's more interesting when considering the other angle: we've had specialised machines that can do sums - usually considered a sign of intelligence in humans and certainly a bar most sentient animals can't cross - for decades now. Is that high performance at a specialised task sufficient evidence of sentience of a pocket calculator? If not (presumably because math is pretty orthogonal to higher order mammals' evolved emotional imperatives to act) what is it about stochastic optimisation of ASCII or pixel inputs with satisfying results that's so very different?

That's not what I mean. I mean the concept of addition. Sure they can't add large numbers but they can to some level understand the ballpark of what adding two large quantities (not even necessarily numbers) together looks like.