1. The problem is to round a number to 3 decimal places at the final answer. 2. The rule for rounding to 3 decimal places is to look at the fourth decimal digit. 3. If the fourth decimal digit is 5 or greater, increase the third decimal digit by 1. 4. If the fourth decimal digit is less than 5, keep the third decimal digit as is. 5. For example, to round $3.141592$ to 3 decimal places: - The third decimal digit is 1 (in 3.141) - The fourth decimal digit is 5 (in 3.1415) - Since 5 is equal to 5, increase the third decimal digit by 1, so 1 becomes 2 - The rounded number is $3.142$ 6. Always perform all calculations first, then round the final result to 3 decimal places as described.