Write the number 0.0000000678 as the product of a single digit number times a power of 10.

Moving the decimal place seven places to the right gives $\boxed{6.78}\times 10^{-8}$.

remove the werid symbols

The number 0.0000000678 can be written as the product of a single digit number and a power of 10: 6.78 × 10^(-8).