# It took OpenAI's agents 130 billion tokens to crack a 90-year-old math problem > Source: > Published: 2026-09-09 15:55:21+00:00 Math is hard. And, apparently, expensive. On Tuesday, OpenAI said its agents had [solved the Navier-Stokes equations](https://www.businessinsider.com/navier-stokes-millennium-prize-problems-2014-10), a 90-year-old set of mathematical formulas that can predict how liquids and gases move. It's so complicated that the Clay Mathematics Institute has offered a [$1 million prize](https://www.businessinsider.com/millennium-prize-problems-million-dollar-prize-2017-12) to any mathematician who finds the solution. OpenAI said that finding the solution required a lot of resources. Its coordinating AI agents sent 2.7 million messages while working on the proof. The effort involved about 10,000 concurrent agents and reached a resolution after 88 hours. Verification took another 17 hours. Such intensive use of AI doesn't come cheap. In a post on X, LisanBench, an LLM benchmark evaluator, estimated that the output tokens alone would cost about $6.5 million at OpenAI's average consumer price. Including the far larger volume of input tokens, the post estimated the total could reach $10 million to $40 million. OpenAI CEO Sam Altman replied, joking that AI was a bubble. OpenAI's announcement that it [solved the age-old mathematics problem](https://www.businessinsider.com/openai-navier-stokes-math-breakthrough-drama-2026-9) was celebrated within the AI industry. It's also been widely criticized after two mathematicians — Tristan Buckmaster and Levent Alpöge — raised questions about how OpenAI used their related research data to train its models. OpenAI denied direct access to their work, but said that it "cannot rule out that de-identified data derived from their usage of our products helped improve our models." The company didn't immediately respond to a request for comment from Business Insider.