Step 1:
The first step to converting 516.123430821 to a fraction is to re-write 516.123430821 in the form p/q where p and q are both positive integers. To start with, 516.123430821 can be written as simply 516.123430821/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 516.123430821, which in this case is 9. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 516.123430821/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 516.123430821/1 each by 1000000000:
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 516.123430821 as a fraction:
37677/73 / 1