2. \( \begin{array}{r}642 \\ \times \quad 50 \\ \hline\end{array} \)

To multiply 642 by 50, you can use a neat trick: instead of doing the multiplication directly, you can first multiply 642 by 10 (which gives you 6420) and then simply shift that result one place to the left (which is the same as multiplying by 5). So, \( 642 \times 50 = (642 \times 10) \times 5 = 6420 \times 5 = 32100 \). If you want to double-check your work, consider breaking it down further! You can view 50 as 5 multiplied by 10. So, you could calculate \( 642 \times 5 \) first, which equals 3210, and then multiply that by 10 to get the final answer: 32100. This confirms that your multiplication is spot on!