Step 1:
The first step to converting 3987680864.9813 to a fraction is to re-write 3987680864.9813 in the form p/q where p and q are both positive integers. To start with, 3987680864.9813 can be written as simply 3987680864.9813/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 3987680864.9813, which in this case is 4. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 3987680864.9813/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 3987680864.9813/1 each by 10000:
Step 3:
Now the last step is to simplify the fraction (if possible) by finding similar factors and cancelling them out, which leads to the following answer for 3987680864.9813 as a fraction:
3987680864/1 / 1