\begin{align*} \frac{10!}{4!6!} & = \frac{10 \times 9 \times 8 \times 7 \times 6!}{4 \times 3 \times 2 \times 1 \times 6!}\\ & = \frac{10 \times 9 \times 8 \times 7}{4 \times 3 \times 2 \times 1}\\ & = \frac{5040}{24}\\ & = 210. \end{align*}