Using the Sales data $($you can copy this data from the Sales data tab to EoW $1),$

$(1$a$)$ Create a column "Promise$=$Shipped Date" with a formula that checks whether the promised date is equal to the shipped date. Create a second column "Days Over$/($Under$)$ to show how many days before or after the promise date customer orders were shipped. How many orders were shipped after the promise date?

$(1$b$)$ Create a column "Extended Price" with a formula that calculates the quantity sold multiplied by the price of the goods sold. Create a second column that calculates the "NetSalesAmt" with a formula to calculate the total price net of shipping costs. As a validity check, create a column "Recalc" that verifies whether "Extended Price" $=$ "NetSalesAmt". Are there any differences and is there any indication of what those might be related to$?$

$(1$c$)$ Assume a sales tax rate of $7\%$ on all customer orders. Create a column "SalesTaxAmt" with a formula to calculate sales taxes to be added to the total price using an absolute reference.