I'm not sure if there is a process in the Casio that can do the whole thing for you. Without knowing that you can still solve the problem. You would just have to do it four times. First solve for X equals 10, then X equals 11, then exit equals 12, and lastly x = 13. Then you add all those answers together. Don't round each answer. Wait to round at the end.
Hi, sorry it took so long to get back to you. You’ve probably already gotten your answer. You would enter those numbers the same way I did the example, but I’m curious why your first & last fractions are to the third power? Usually the first fraction in a binomial would be to the power of the second number in the combination, so in your case a six. And the second fraction would be to the power of N minus X which would be 15-6 or the ninth power
Fahim Khan thanks for taking the time to comment. I just posted a bunch of videos last week for the FX 115. It’s not identical to the FX 300 but you might find them helpful.