Question

0.0136 g + 2.70 × 10-4 g - 4.21 × 10-3 g = ?

How many digits to the right of the decimal point should be used to report the result?

Answer 1

The answer is 2 for the first one and its 9.66x10^-3g for the second one.

Answer 2

The rule that applies in this evaluation is that in addition or subtraction operations, the answer (total/difference) should not be more accurate than the least accurate term. In this case, the number with least sig fig is 2.70 or 4.21. The answer here is 9.66 x10-3.