Step 1:
The first step to converting 16398.404999887 to a fraction is to re-write 16398.404999887 in the form p/q where p and q are both positive integers. To start with, 16398.404999887 can be written as simply 16398.404999887/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 16398.404999887, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 16398.404999887/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 16398.404999887/1 each by 1000000000:
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 16398.404999887 as a fraction:
81992/5 / 1