Question

the number is between 0 and 999999​

Answer 1

Answer: 4

3

How many numbers between 0 and 999,999 are there whose digits sum to r

In generating a function for the answer, here is what I came to.

We have a maximum of 6 number slots to use to sum to r.

Then e1+e2+e3+e4+e5+e6=r

And since each slot has the capacity to be a number between 0 and 9, then ei=(1+x1+x2+x3+x4+x5+x6+x7+x8+x9),

and the generating function is therefore (1+x1+x2+x3+x4+x5+x6+x7+x8+x9)6.

Do I have this generating function correct?

Step-by-step explanation:

Answer 2

999998 are the no of numbers