Round 6.7832×1046.7832 \times 10^46.7832×104 to 3 significant figures.
6.78×1046.78 \times 10^46.78×104
6.8×1046.8 \times 10^46.8×104
6.783×1046.783 \times 10^46.783×104
6.79×1046.79 \times 10^46.79×104