Chain-of-thought arithmetic, step by step

The prompt

The odd numbers in this group add up to an even number: 15, 32, 5, 13, 82, 7, 1.
Solve by breaking the problem into steps. First, identify the odd numbers, add them, and indicate whether the result is odd or even.

Expected result

Odd numbers identified as 15, 5, 13, 7, 1 → sum = 41 → odd, so the model correctly reports the original claim ("adds up to an even number") is FALSE, with its work shown.

Why it works

Classic chain-of-thought math prompt: forcing the model to break the task into explicit steps (identify → add → classify) substantially improves accuracy over asking for the answer directly.