Report your answer in the correct number of sig figs. 0.007 + 0.02 = 70/0.375 = 0.009/101 =
The Correct Answer and Explanation is:
Let’s solve each problem and report the final answer using the correct number of significant figures (sig figs).
1. 0.007 + 0.02 = ?
To add or subtract values, we look at the number of decimal places, not sig figs.
- 0.007 has 3 decimal places
- 0.02 has 2 decimal places
So the answer must be rounded to 2 decimal places.
Calculation:
0.007 + 0.02 = 0.027
Rounded to 2 decimal places → 0.03
✅ Final Answer: 0.03
2. 70 ÷ 0.375 = ?
For multiplication and division, the result must be reported using the least number of sig figs in the inputs.
- 70 has 1 significant figure (unless written as 7.0 × 10¹, which would mean 2 sig figs)
- 0.375 has 3 significant figures
So the answer must have 1 significant figure.
Calculation:
70 ÷ 0.375 = 186.666…
Rounded to 1 sig fig → 200
✅ Final Answer: 200
(Note: It’s written as 200 to 1 sig fig. If the trailing zeros are significant, you would write it as 2.0 × 10², but here, assume 200 has just 1 sig fig.)
3. 0.009 ÷ 101 = ?
- 0.009 has 1 significant figure
- 101 has 3 significant figures
The answer must have 1 significant figure.
Calculation:
0.009 ÷ 101 ≈ 8.91 × 10⁻⁵
Rounded to 1 sig fig → 9 × 10⁻⁵
✅ Final Answer: 9 × 10⁻⁵
Explanation
Significant figures, or sig figs, are the digits in a number that carry meaningful information about its precision. They are especially important in scientific measurements and calculations, as they reflect the certainty in the data provided. The rules for determining how many sig figs to report depend on the mathematical operation being performed.
When adding or subtracting, the key is to look at the number of decimal places, not the number of sig figs. The result should be rounded to the same number of decimal places as the measurement with the fewest. In the case of 0.007 + 0.02, 0.02 only has two decimal places, so the answer is rounded to two decimal places, resulting in 0.03.
For multiplication or division, the result must be rounded to the same number of sig figs as the input with the least number of significant figures. In 70 ÷ 0.375, since 70 has only one significant figure (no decimal point or scientific notation shown), the result is rounded to one sig fig: 200. Similarly, in 0.009 ÷ 101, the number 0.009 has only one significant figure, so the final answer is 9 × 10⁻⁵.
Understanding these rules helps maintain accuracy and consistency in reporting scientific results. It prevents overstating the precision of measurements and ensures that conclusions drawn from calculations remain valid and trustworthy.
