This paper investigates the impact of Chain-of-Thought (CoT) examples in In-Context Learning (ICL) on improving the mathematical reasoning ability of state-of-the-art large-scale language models (LLMs). Specifically, we find that, for powerful models such as the Qwen2.5 series, existing CoT examples do not improve performance compared to Zero-Shot CoT, and instead contribute to output format alignment. Furthermore, we find that even enhanced CoT examples composed of answers from superior models fail to improve the model's reasoning ability, with the model tending to ignore examples and focus on instructions. Overall, this study highlights limitations in improving mathematical reasoning ability with the current ICL+CoT framework and calls for a reexamination of the ICL paradigm and the definition of examples.