Final answer:
This mathematical question revolves around rounding principles for percentages and addition/subtraction of numbers with different decimal places. Significant figures play a crucial role, as the number with the least number of decimal places dictates the precision for the rounded result.
Step-by-step explanation:
The subject in question is about rounding percentages and sums of numbers with regard to their decimal places. The concept is important in Mathematics, particularly when dealing with precision and significant figures.
For instance, a calculator might give an answer of 201.867. This should be rounded to the hundredth place because the instructions specify rounding to the nearest hundredth when the number ends in 0. Therefore, the final answer is 201.87 since 7 (the digit following the hundredth place) is greater than 5.
When rounding sums, like 137.3 s (to the tenths place) plus 70.90 s (to the hundredths place), the sum is 208.20 s. This should be rounded to the tenths place because 137.3 s, having the least precise measurement, dictates the rounding precision. The result would be rounded to 208.2 s.
Similarly, subtraction should consider significant figures. For the operation 78,500 m - 362 m; since 78,500 m is known only to the hundreds place, the result should be rounded to that same place, yielding 78,100 m. Always remember: when performing addition or subtraction, round off the result to the same number of decimal places as the number with the least number of decimal places.