Step 1:
The first step to converting 7921.638 to a fraction is to re-write 7921.638 in the form p/q where p and q are both positive integers. To start with, 7921.638 can be written as simply 7921.638/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 7921.638, which in this case is 3. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 7921.638/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 7921.638/1 each by 1000:
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 7921.638 as a fraction:
87138/11 / 1