Step 1:
The first step to converting 1245.7873171997 to a fraction is to re-write 1245.7873171997 in the form p/q where p and q are both positive integers. To start with, 1245.7873171997 can be written as simply 1245.7873171997/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 1245.7873171997, which in this case is 10. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 1245.7873171997/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 1245.7873171997/1 each by 10000000000:
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 1245.7873171997 as a fraction:
41111/33 / 1