ChatGPT and Cursor both failed hard. Even after walking them backwards through the flaws in their answers they just refused to see it. When I stated flat out what the answer was ChatGPT agreed in the end. Cursor did not. Cursors initial reply was -200g. Then I challenged "But I did not tare it after adding the almonds." and again it failed with: "That doesn't change the final reading: it still displays -200g.". When I walked it back further with "If I put the container on the food scale, tare it and remove the container, what does the scale read?" it correctly replied "negative the weight of the empty container" but ... when I asked "So does this impact the agents answer to my original question?" it replied "No, it doesn't change the answer—the scale still reads -200g". LLMs are NOT good at even basic numeric accounting.