Numerous.ai is an AI-powered spreadsheet plugin that integrates ChatGPT into Google Sheets and Excel, allowing users to easily perform various tasks directly within their spreadsheets. The core features of Numerous.ai include the ability to prompt ChatGPT and perform tasks using the =AI() function, train AI to do repetitive tasks with the =INFER() function, generate text with the =WRITE() function, create formulas in plain English, and get explanations for complex formulas.Some use cases for Numerous.ai include automating data categorization, streamlining formatting, language tasks like extracting text and performing sentiment analysis, content generation such as marketing copy and customer responses, as well as generating and explaining formulas.To use Numerous.ai, users need to install the Google Sheets add-on or Microsoft Excel add-in. Once installed, users can access Numerous.ai by clicking on Extensions -> Numerous.ai -> Open sidebar in their spreadsheet. They can then utilize the various functions to prompt ChatGPT, train AI, generate text, create formulas, and get formula explanations directly within their spreadsheet.