Step 1:
The first step to converting 418640387.78639 to a fraction is to re-write 418640387.78639 in the form p/q where p and q are both positive integers. To start with, 418640387.78639 can be written as simply 418640387.78639/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 418640387.78639, which in this case is 5. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 418640387.78639/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 418640387.78639/1 each by 100000:
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 418640387.78639 as a fraction:
418640387/1 / 1