It doesn't "know" what words are, only tokens. Use this tool (https://platform.openai.com/tokenizer) to see how it tokenizes and note clearly that it does not always do so on word boundaries. "Including" is two tokens: "In" and "cluding". In fact it's context-dependent: "Gravitas" is three on its own ("G", "rav" and "itas") or sometimes two ("grav" and "itas"). As they note on that page: "A helpful rule of thumb is that one token generally corresponds to ~4 characters of text for common English text." It "knows" nothing about words and we already know it's very bad at math so this result is entirely unsurprising.