Answer:
7.8 × 10^-4
Step-by-step explanation:
Although this answer is perfectly O.K., most commonly the base, or the 0.00078, is written as a number with just one digit to the left of the decimal.
To format your number in this way, we'll multiply the .00078 by 10, 4 time(s), making it a 7.8.
We do this, because each multiplication by 10 moves the decimal point to the right one digit.
But in order to keep our number the same number, we must have a × 10-4 next to the 7.8.
So, the final answer is 7.8 × 10^-4
