Use the definition of the derivative of a vector to find scalar triple product.

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How to find $(u(t)v(t)×w(t))'$ by using definition of the derivative of a vector. I only know how to find $(u(t)v(t))'$ or $(v(t)×w(t))'$

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With implicit summation over repeated indices,$$\begin{align}\frac{d}{dt}(u\cdot v\times w)&=\frac{d}{dt}(\epsilon_{ijk}u_iv_jw_k)\\&=\epsilon_{ijk}u^\prime_iv_jw_k+\epsilon_{ijk}u_iv^\prime_jw_k+\epsilon_{ijk}u_iv_jw^\prime_k\\&=u^\prime\cdot v\times w+u\cdot v^\prime\times w+u\cdot v\times w^\prime,\end{align}$$where the second $=$ uses the product rule.