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## How to determine significant figures with addition and subtraction.

Precision is determined by DECIMAL POINT, not number of significant figures. When adding and subtracting, the NUMBER of significant figures is irrelevant. The DECIMAL PLACE is what determines precision. In this case, 8.4x104 goes out to the thousands place (0.4x104 = 4000) and 1.03x105 also goes out to the thousands place (0.03x105 = 3000). Thus, your answer must go out to the thousands place as well.

You only count significant figures when multiplying and dividing. Once again, look at the example in Module 1. Had he been multiplying or dividing these two numbers, his answer should have had only 2 significant figures. However, he was not multiplying or dividing, so counting significant figures is irrelevant.

In general, I count 1/4 of the questions credit off for all significant figure errors.

Tags: Chemistry, Math, Physics, Signigicant Figures
Last update:
2019-01-29 20:51
Author:
Sue
Revision:
1.8 