Step 1:
The first step to converting 12879.257421968 to a fraction is to re-write 12879.257421968 in the form p/q where p and q are both positive integers. To start with, 12879.257421968 can be written as simply 12879.257421968/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 12879.257421968, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 12879.257421968/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 12879.257421968/1 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 12879.257421968 as a fraction:
51517/4 / 1