# How do these cross products work

I do not understand the properties of these cross product problems.

For #1: $(\vec{i} \times \vec{j} ) \times \vec{k} = \vec{k} \times \vec{k} = 0$. So I assume that any vector, like "$\vec{k}$" crossed with itself will equal 0?

Then I have no idea how to solve these problems:

Number 2: $\text{ }$$\vec{k}\times (\vec{i} - 2\vec{j}) 3: \text{ }$$(\vec{j}-\vec{k}) \times (\vec{k} - \vec{j})$

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