Final answer:
The difference between the estimated sum to the nearest tenth and the exact sum involves the precision of the numbers used. Estimation rounds the numbers to the nearest tenth before calculating the sum, leading to potential rounding errors, while the exact sum uses the precise figures for a more accurate result.
Step-by-step explanation:
The difference between the sum of a set of numbers estimated to the nearest tenth and the exact sum lies in the level of precision. When numbers are estimated to the nearest tenth, any digits beyond the tenth's place are not considered, which may lead to a rounding error. On the other hand, the exact sum takes into account all of the digits in the original numbers, which gives a more precise sum. For instance, if you have the measurements 16.7 g and 5.24 g, and you want to estimate the sum to the nearest tenth, you would first round the second number to 5.2 g since the first number is only precise to the tenths place. The estimated sum would then be 16.7 g + 5.2 g = 21.9 g. If you calculate the exact sum, it would be 16.7 g + 5.24 g = 21.94 g. In summary, for addition and subtraction problems, the answer should be rounded to the same number of decimal places as the measurement with the least number of decimal places.