$1\mathrm{.}3$ Construct a formula in cell E$5)$ to calculate the total amount for transaction $578.$ Be sure to appropriately reference the transaction amount in cell C$5)$ and the sales tax amount in cell D$5)$ so you can reuse your formula to calculate the total for the remaining transactions.

$1\mathrm{.}4$ Copy the formula you used in cell E$5)$ down to calculate the total for the remaining transactions.

$1\mathrm{.}5$ Use the SUM function to calculate the grand total for all the transactions in cell E$18).$