Posted by Joanne on .
Expressed to the correct number of significant figures, the sum of two masses is 445.2 grams. WHich two masses produce this answer?
1) 210.10 g+235.100g
2)210.100 g + 235.10 g
3) 210.1 g + 235.1 g
4) 210.10 g+ 235.10 g
I think the answer is 2 but I don't know the reason why.

Math 
Dr Russ,
The answer is 3. Usually the minimum number of decimal places (dp) determines the number of decimal places in the answer. Here both values have one dp so the answer is to one dp.
the results for the others are
1)445.20
2)445.20
4)445.20