Step 1:
The first step to converting 399418577.79821 to a fraction is to re-write 399418577.79821 in the form p/q where p and q are both positive integers. To start with, 399418577.79821 can be written as simply 399418577.79821/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 399418577.79821, which in this case is 5. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 399418577.79821/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 399418577.79821/1 each by 100000:
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 399418577.79821 as a fraction:
399418577/1 / 1