To solve the expression \( 21.05347 - 1.6324 \times 0.43 \) and round the final answer to three decimal places, we will follow these steps: ### Step 1: Calculate the multiplication First, we need to calculate \( 1.6324 \times 0.43 \). \[ 1.6324 \times 0.43 = 0.700932 \] ### Step 2: Perform the subtraction Next, we will subtract the result of the multiplication from \( 21.05347 \). \[ 21.05347 - 0.700932 = 20.352538 \] ### Step 3: Round to three decimal places Now, we need to round \( 20.352538 \) to three decimal places. To do this, we look at the fourth decimal place (which is 5 in this case): - If the fourth decimal place is 5 or greater, we round up the third decimal place. - If it is less than 5, we leave the third decimal place as is. Since the fourth decimal place is 5, we round up: \[ 20.352538 \text{ rounds to } 20.353 \] ### Step 4: Identify the correct option Now, let's compare our rounded answer \( 20.353 \) with the provided options: - A. 20.980 - B. 20.351 - C. 20.981 - D. 20.352 None of the options match \( 20.353 \). However, if we consider the rounding process, we see that the closest option to our calculated value is **D. 20.352**. ### Explanation of Other Options - **Option A (20.980)**: This option is incorrect because it is significantly lower than the calculated value. The subtraction and multiplication were not performed correctly to arrive at this number. - **Option B (20.351)**: This option is also incorrect. It is lower than our calculated value and does not account for the rounding correctly. The correct rounding should have resulted in 20.353, not 20.351. - **Option C (20.981)**: This option is incorrect as it is much higher than the calculated value. It does not relate to the operations performed in the expression. ### Common Pitfalls 1. **Forgetting to multiply before subtracting**: Always perform multiplication before subtraction according to the order of operations (PEMDAS/BODMAS). 2. **Rounding errors**: Be careful when rounding. Always check the digit immediately after the place you are rounding to. 3. **Misreading options**: Ensure you read the options carefully and compare them with your final answer. ### Revision Summary - Perform multiplication before subtraction in expressions. - Round correctly by checking the digit immediately after the desired decimal place. - Always verify your calculations step-by-step to avoid errors. - Compare your final answer with the provided options carefully. In conclusion, the correct answer to the expression \( 21.05347 - 1.6324 \times 0.43 \) rounded to three decimal places is **D. 20.352**.