2^5－5×2^4＋10×2³－10×2²＋5×2－1
=2^5﹢5×2^4×﹙﹣1﹚＋10×2³×1²﹢10×2²×﹙﹣1﹚³＋5×2×﹙﹣1﹚^4﹢﹙－1﹚^5
=(2﹢﹤﹣1﹥﹚^5
=1^5
=1