Question

three numbers which is equal to the factorial of each number individually

Answer 1

This ought to get you started: The largest digit is clearly either 5 or 6, since that's the only way to make the sum three-digit. 6 can be ruled out pretty easily, since any number larger than 6! has either a 7,8 or a 9 in the hundreds digit.

So the largest digit is 5. There aren't too many options left to test. Try it out, and see what works.