Step 1:
The first step to converting 638668.78950048 to a fraction is to re-write 638668.78950048 in the form p/q where p and q are both positive integers. To start with, 638668.78950048 can be written as simply 638668.78950048/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 638668.78950048, which in this case is 8. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 638668.78950048/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 638668.78950048/1 each by 100000000:
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 638668.78950048 as a fraction:
638669/1 / 1