To determine which of the given numbers is expressed with the correct number of significant figures, we need to understand the rules of significant figures. Significant figures are the digits in a number that contribute to its precision. This includes all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion. ### Analyzing Each Option **Option A: 0.004560** - **Significant Figures**: The leading zeros (0.00) are not significant. The digits 4, 5, 6, and the trailing zero (0) after the 6 are significant. Therefore, this number has **4 significant figures** (4, 5, 6, and the trailing 0). **Option B: 123.45** - **Significant Figures**: All digits in this number are non-zero and thus significant. Therefore, this number has **5 significant figures** (1, 2, 3, 4, and 5). **Option C: 1000** - **Significant Figures**: The number 1000 can be ambiguous. If it is written without a decimal point, it typically has **1 significant figure** (the '1'), unless specified otherwise (e.g., in scientific notation). If it were written as 1000. or in scientific notation (1.000 x 10^3), it would have 4 significant figures. However, as it stands, we consider it to have **1 significant figure**. **Option D: 0.0500** - **Significant Figures**: The leading zeros (0.0) are not significant. The digits 5 and 0 are significant, and the trailing zero (0) after the 5 is also significant. Therefore, this number has **3 significant figures** (5, 0, and the trailing 0). ### Summary of Significant Figures for Each Option - **A: 0.004560** - 4 significant figures - **B: 123.45** - 5 significant figures - **C: 1000** - 1 significant figure (ambiguous) - **D: 0.0500** - 3 significant figures ### Correct Answer The question asks for the number that is expressed with the correct number of significant figures. Since all options are valid in terms of significant figures, we need to identify which one is most commonly accepted in scientific contexts. **Final Answer: B. 123.45** is the best option because it clearly has 5 significant figures without ambiguity. ### Why Other Options Are Weaker - **Option A (0.004560)**: While it has 4 significant figures, it is less straightforward than option B, which has all non-zero digits. - **Option C (1000)**: This is ambiguous and can be interpreted in multiple ways, making it less reliable. - **Option D (0.0500)**: Although it has 3 significant figures, it is less commonly used than option B in contexts requiring clarity. ### Revision Summary - Significant figures include all non-zero digits, zeros between significant digits, and trailing zeros in decimal numbers. - Leading zeros are not significant. - The number of significant figures can affect the precision of measurements and calculations. - Always clarify ambiguous numbers (like 1000) to avoid misinterpretation in scientific contexts.