how many significant figures does the sum of 8.520 the 2.7 contain?
When adding or subtracting the sum is to the least number of decimal places
When multiplying or dividing the sum is least number of Sig figs.
Two
To determine the number of significant figures in the sum of two numbers, you need to consider the number with the fewest significant figures. In this case, the number 2.7 has only two significant figures.
When you add or subtract numbers, the result should be rounded to the same number of decimal places as the number with the fewest decimal places. In this case, since 2.7 has one decimal place, your sum should also have one decimal place.
So, the sum of 8.520 and 2.7 would be rounded to 11.2, which has two significant figures.