Step 1:
The first step to converting 603.99635816805 to a fraction is to re-write 603.99635816805 in the form p/q where p and q are both positive integers. To start with, 603.99635816805 can be written as simply 603.99635816805/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 603.99635816805, which in this case is 11. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 603.99635816805/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 603.99635816805/1 each by 100000000000:
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 603.99635816805 as a fraction:
165495/274 / 1