Someone . i'll mark you as brainliest : )

Scientific notation are super long numbers that are shortened by a decimal and an exponent. In my opinion, it's much more fun to write zeroes over and over, but nobody cares about my opinion, haha. 
So how to make a number a scientific notation:
Step one: Identify the number. (ex. 0.000025)
Step two: Get rid of the zeroes for a second. We will get to that later. (25)
Step three: Put a decimal point between the two numbers. If there are three or more, but the decimal point before the last left number. (2.5)
Step four: Break! (math is boring at times)
Step five: Put the decimal into the scientific notation format. A scientific notation format is _._*10^_. The blanks represent the places that the numbers should go into. The power can be negative or positive, more on that later. For this equation, we will put the decimal before the times 10. (2.5*10^_)
Step six: Now we have to determine the value of the power. That is very easy. First, let’s go back to the decimal. 0.000025. Since we put the after decimal point between 2 and 5, We will count to the other initial decimal point. For this one, there are 5 decimal points. So that means the value of the power is 5. If the original number was positive, you would put the decimal point into the large number, count the number of well….numbers there are between the decimal point and the last number.
Step seven: Set it up! (2.5*10^5)Done!!!
For number two, 2x10^-4(sand)/1x10^-5(cell) = 2x10^1. SO this means the answer is 20 times.