How do you use Pascal's triangle to calculate the binomial coefficient of ((9), (4))?

Pascal's triangle row and column numbering starts at 0, so for $\left(\setminus \frac{9}{4}\right)$ find the tenth row, fifth column, which is 126. You can check this with a calculator: 9C4 = \frac{9!}{4!*5!} = 126.