Step 1:
The first step to converting 12406.521078567 to a fraction is to re-write 12406.521078567 in the form p/q where p and q are both positive integers. To start with, 12406.521078567 can be written as simply 12406.521078567/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 12406.521078567, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 12406.521078567/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 12406.521078567/1 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 12406.521078567 as a fraction:
285350/23 / 1