Explanation
This formula uses the value in cell F6 for a lookup value, the range B5:C10 for the lookup table, 2 to indicate "2nd column", and zero as the last argument to force an exact match.
Although in this case we are mapping numeric inputs to numeric outputs, the same formula will handle text values for both inputs and outputs.
Alternative with CHOOSE
If you have a limited number of inputs, and if the inputs are are numbers starting with 1, you can also use the CHOOSE function. For the example shown the equivalent formula based on CHOOSE is:
=CHOOSE(F6,10,81,17,23,13,31)
The choose function is unwieldy for large amounts of data but for smaller data sets that map to a 1-based index, it has the advantage of being an "all in one" solution.