Step 1:
The first step to converting 686556579.3984 to a fraction is to re-write 686556579.3984 in the form p/q where p and q are both positive integers. To start with, 686556579.3984 can be written as simply 686556579.3984/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 686556579.3984, which in this case is 4. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 686556579.3984/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 686556579.3984/1 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 686556579.3984 as a fraction:
686556579/1 / 1