Step 1:
The first step to converting 1396290236.1643 to a fraction is to re-write 1396290236.1643 in the form p/q where p and q are both positive integers. To start with, 1396290236.1643 can be written as simply 1396290236.1643/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 1396290236.1643, which in this case is 4. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 1396290236.1643/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 1396290236.1643/1 each by 10000:
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 1396290236.1643 as a fraction:
1396290236/1 / 1