=PRODUCT(X,X) Multiply 2 ways
=SUM(X-X) Subtract 2 ways
The VLOOKUP function
The VLOOKUP function is a handy one to know when you want Excel to lookup a value in one place and insert it in another. For example, let’s say you have a list of all of your customers on a sheet named “Accounts” and an invoice on another sheet named “Invoice”. When you type in their account number on the Invoice, you want Excel to fill in the name of the customer and their address (and this information is included for all customers on the Accounts sheet). A VLOOKUP will do this for you.
Since we want an exact match, type False in the Range_lookup field
C2 is the Look_up value; Customers is the Table_array; 2 is the Col_index_num