Step 1:
The first step to converting 1298.7876891 to a fraction is to re-write 1298.7876891 in the form p/q where p and q are both positive integers. To start with, 1298.7876891 can be written as simply 1298.7876891/1 to technically be written as a fraction.
Step 2:
Next, we will count the number of fractional digits after the decimal point in 1298.7876891, which in this case is 7. For however many digits after the decimal point there are, we will multiply the numerator and denominator of 1298.7876891/1 each by 10 to the power of that many digits. So, in this case, we will multiply the numerator and denominator of 1298.7876891/1 each by 10000000:
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 1298.7876891 as a fraction:
42860/33 / 1