Calculating the number of permutations whose sum makes N where only single digits are allowed

Question

If we want to know the number of ways that $N$ can be made by taking the sum of $T$ numbers we can use $\dfrac{(N+(T-1))!}{(N!\times (T-1)!)}$ however, how would you be able to calculate the number of ways that $N$ can be made by taking the sum of $T$ numbers where all numbers are only single digit numbers?