Answer:
2.8 · 10^(-9)
Step-by-step explanation:
I'd suggest you do this problem through two separate multiplications:
First, 0.4·0.7 = 0.28, or 2.8 · 10^(-1)
Second, 10^(-6) · 10^(-2) = 10^(-8), and so the final result is
2.8 · 10^(-1) · 10(-8) = 2.8 · 10^(-9)
Please note: negative exponents (such as -9, above) should be enclosed in parentheses for added clarity.
