Step-by-step explanation:

On the Data tab, in the Outline group, click Subtotal. The Subtotal dialog box is displayed.

In the At each change in box, click the nested subtotal column. ...

In the Use function box, click the summary function that you want to use to calculate the subtotals. ...

Clear the Replace current subtotals check box.

Step-by-step explanation:

4.2 ,

Q no.6

hope it's helpful to U (◠‿◕)