Step 1:
The first step to converting 629.6642408054 to a fraction is to re-write 629.6642408054 in the form p/q where p and q are both positive integers. To start with, 629.6642408054 can be written as simply 629.6642408054/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 629.6642408054, which in this case is 10. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 629.6642408054/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 629.6642408054/1 each by 10000000000:
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 629.6642408054 as a fraction:
86264/137 / 1