How Many Significant Figures?

• 4.501 has four significant figures.
• 400 has one significant figure.
• The two zeros after the value 4 are placeholders.
• 0.0040 has two significant figures.
• The three zeros in front of the value 4 are placeholders. The zero following the value 4 is significant.
• 4,101 has four significant figures.
• 0.400 has three significant figures.
• Only the zero in front of the value 4 is a placeholder.