While VLOOKUP is probably the simpler solution, the following formula will also work:
where C is the letter of your "number" column, Input is the cell that your look up value is in and LookupRange is the array of cells, organized vertically, that you want to compare Input to.
Also, you may need to offset the return value from MATCH if your table does not start in row 1. Example:
where X is the number of rows to offset.
Also worth experimenting with is the final input for the MATCH formula, as this can affect whether Excel will match in-between values with greater then or less then values (accepted inputs are: -1, 0, 1).