Remember that $80$ in expanded form is

\[ 8 \times 10. \]

Therefore,

\begin{align*} 80\div 8 &= \\[5pt] 8 \times 10 \div 8 &. \end{align*}

Then, we swap the order of the multiplication and division:

\begin{align*} 8 \times 10 \div 8 &=\\[5pt] 8 \div 8 \times 10 &=\\[5pt] ({\color{blue}{8 \div 8}}) \times 10 &=\\[5pt] {\color{blue}{1}}\times 10 &=\\[5pt] 10& \end{align*}

Therefore, $80\div 8 = 10.$

Remember that $80$ in expanded form is

\[ 8 \times 10. \]

Therefore,

\begin{align*} 80\div 2 &= \\[5pt] 8 \times 10 \div 2 &. \end{align*}

Then, we swap the order of the multiplication and division:

\begin{align*} 8 \times 10 \div 2 &=\\[5pt] 8 \div 2 \times 10 &=\\[5pt] ({\color{blue}{8 \div 2}}) \times 10 &=\\[5pt] {\color{blue}{4}}\times 10 &=\\[5pt] 40& \end{align*}

Therefore, $80\div 2 = 40.$

Remember that $160$ is the same as $16$ tens. So, we have

\[ 160 = 16 \times {10}. \]

Therefore,

\begin{align*} 160 \div 8 &= \\[5pt] 16 \times 10 \div 8 &. \end{align*}

Then, we swap the order of the multiplication and division:

\begin{align*} 16 \times 10 \div 8 &=\\[5pt] 16 \div 8 \times 10 &=\\[5pt] ({\color{blue}{16 \div 8}}) \times 10 &=\\[5pt] {\color{blue}{2}}\times 10 &=\\[5pt] 20& \end{align*}

Therefore, $160\div 8 = 20.$

Remember that $500$ is the same as $50$ tens. So, we have

\[ 500 = 50 \times {10}. \]

Therefore,

\begin{align*} 500 \div 2 &= \\[5pt] 50 \times 10 \div 2 &. \end{align*}

Then, we swap the order of the multiplication and division:

\begin{align*} 50 \times 10 \div 2 &=\\[5pt] 50 \div 2 \times 10 &=\\[5pt] ({\color{blue}{50 \div 2}}) \times 10 &=\\[5pt] {\color{blue}{25}}\times 10 &=\\[5pt] 250& \end{align*}

Therefore, $500\div 2 = 250.$

Remember that $5,500$ is the same as $55$ hundreds. So, we have

\[ 5,500 = 55 \times {100}. \]

Therefore,

\begin{align*} 5,500\div 5&= \\[5pt] 55 \times 100 \div 5 &. \end{align*}

Then, we swap the order of the multiplication and division:

\begin{align*} 55 \times 100 \div 5 &=\\[5pt] 55 \div 5 \times 100 &=\\[5pt] ({\color{blue}{55 \div 5}}) \times 100 &=\\[5pt] {\color{blue}{11}}\times 100 &=\\[5pt] 1,100& \end{align*}

Therefore, $5,500\div 5 = 1,100.$

We need to calculate $\$4,200\div 6.$

Remember that $4,200$ is the same as $42$ hundreds. So, we have

\[ 4,200 = 42 \times {100}. \]

Therefore,

\begin{align*} 4,200\div 6&= \\[5pt] 42 \times 100 \div 6 &. \end{align*}

Then, we swap the order of the multiplication and division:

\begin{align*} 42 \times 100 \div 6 &=\\[5pt] 42 \div 6 \times 100 &=\\[5pt] ({\color{blue}{42 \div 6}}) \times 100 &=\\[5pt] {\color{blue}{7}}\times 100 &=\\[5pt] 700& \end{align*}

Therefore, each grandchild will receive $\$700.$