VLOOKUPs are used to match a value you are looking for in a table, and retrieve another value which corresponds to it.

The structure of a VLOOKUP is: =VLOOKUP(lookup_value, table_array, col_index_num, [range_lookup])

Where lookup_value is the value you want the table to match (this should be the first column in the range), table_array is the whole range of values in the table, col_index_num is the number of columns to the right of the lookup value you wish the function to return (index begins at 1), and [range_lookup] is whether you want the lookup values to be an exact (FALSE) or approximant (TRUE) match. Default is false.

For example, suppose we want to find how many McDonalds are in a particular state, given the appropriate data. We can easily find that value using VLOOKUP as shown below for North Carolina.