Step 1:
The first step to converting 21388.853928638 to a fraction is to re-write 21388.853928638 in the form p/q where p and q are both positive integers. To start with, 21388.853928638 can be written as simply 21388.853928638/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 21388.853928638, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 21388.853928638/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 21388.853928638/1 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 21388.853928638 as a fraction:
128333/6 / 1