To add the two numbers in scientific notation:
\[ 7 \times 10^{-12} + 8 \times 10^{-12} = (7 + 8) \times 10^{-12} = 15 \times 10^{-12} \]
Now, to express it in proper scientific notation, we can rewrite \(15\) as \(1.5 \times 10^1\), giving us:
\[ 15 \times 10^{-12} = 1.5 \times 10^1 \times 10^{-12} = 1.5 \times 10^{-11} \]
So, the final result is:
\[ 1.5 \times 10^{-11} \]