VLOOKUP searches for a value in the first column of a table. At the match row, it retrieves a value from the specified column.
Use the IFERROR function to trap and handle errors produced by other formulas or functions. IFERROR checks for the following errors: #N/A, #VALUE!, #REF!, #DIV/0!, #NUM!, #NAME?, or #NULL!.
The purpose of the SUMPRODUCT function is to multiply, then sum, arrays. If only one array is supplied, SUMPRODUCT will simply sum the items in the array. Up to 30 arrays can be supplied.