Question

Scientific Notation Online Practice
Complete this assessment to review what you've learned. It will not count toward your grade.
8 of 158 of 15 Items
















Question
Which expression is equal to 5.1×10−3
?(1 point)
Responses

2.9×10−3+1.2×10−3
2.9 times 10 negative cubed plus 1.2 times 10 negative cubed

3.5×103+1.6×10−6
3.5 times 10 cubed plus 1.6 times 10 superscript negative 6 baseline

3.9×10−3+1.2×10−3
3.9 times 10 negative cubed plus 1.2 times 10 negative cubed

2.2×10−1+2.9×10−2

Answer 1

To determine which expression is equal to \(5.1 \times 10^{-3}\), we need to evaluate the responses one by one:

1. **\(2.9 \times 10^{-3} + 1.2 \times 10^{-3}\)**
\[
2.9 \times 10^{-3} + 1.2 \times 10^{-3} = (2.9 + 1.2) \times 10^{-3} = 4.1 \times 10^{-3} \quad \text{(not equal)}
\]

2. **\(3.5 \times 10^{3} + 1.6 \times 10^{-6}\)**
\[
3.5 \times 10^{3} + 1.6 \times 10^{-6} \quad \text{(not equal, as one is positive exponent and the other is negative)}
\]

3. **\(3.9 \times 10^{-3} + 1.2 \times 10^{-3}\)**
\[
3.9 \times 10^{-3} + 1.2 \times 10^{-3} = (3.9 + 1.2) \times 10^{-3} = 5.1 \times 10^{-3} \quad \text{(equal)}
\]

4. **\(2.2 \times 10^{-1} + 2.9 \times 10^{-2}\)**
Let's convert \(2.2 \times 10^{-1}\) to the same exponent:
\[
2.2 \times 10^{-1} = 22 \times 10^{-2}
\]
Now,
\[
22 \times 10^{-2} + 2.9 \times 10^{-2} = (22 + 2.9) \times 10^{-2} = 24.9 \times 10^{-2}
\]
Converting this back to a power of \(10^{-3}\):
\[
24.9 \times 10^{-2} = 249 \times 10^{-3} \quad \text{(not equal)}
\]

From the evaluations, we see that the correct response is:

**3.9×10−3 + 1.2×10−3**