What is 3.1415 + 6.25 rounded to the nearest thousandths place?

To add decimals, vertically align the numbers so that the decimals are lined up. You can pad the shorter decimals by adding zeros to the end, and then add up the numbers:
3.1415
+6.2500
9.3915
Since the question asks to round the sum to the nearest thousandth, we must look at the third digit after the decimal point which contains the digit 1. Since the number to the right of the digit 1 is 5, we must round the thousandths digit 1 up to 2. Thus, the correct answer is: 9.392