Final answer:
The result of the arithmetic expression 0.009 - 901 + 1007.9 - 0.9 is 106.0, when rounded to the least number of decimal places present in the original numbers.
Step-by-step explanation:
The student asked about the result of the arithmetic expression 0.009 - 901 + 1007.9 - 0.9. To solve this, we can follow the steps of addition and subtraction from left to right:
- 0.009 - 901 = -900.991
- -900.991 + 1007.9 = 106.909
- 106.909 - 0.9 = 106.009
Now, we need to consider significant figures. Since the numbers we are adding and subtracting have different numbers of decimal places, the final answer should be rounded to the least number of decimal places present in the original numbers, which is one decimal place. Therefore, the final answer rounded to one decimal place is 106.0.