Write the statement that enables the variable numberOfInvoices to keep track of the number of the invoices calculated(i. e. each time the Calculate button is clicked, the value of numberOfInvoices increases by one and also write the statement that enables total OfInvoices to keep track of the sum of the total of each invoice calculated( i. e. when the Calculate button is clicked the second time, it records the sum of the first invoice and the second invoice, and so on)

Write the statement that enables the variable totalOfInvoices to keep track of the average of the totals of the invoices calculated (i. e. when the Calculate button is clicked the first time, it records the total of the first invoice, when it is clicked the second time, it records the average of the first and second incoice, and so on)

Put the code as Visual Studio.