I'm trying to update a cell "A1" based on a cell value in "B1":

If cell value in B1 < 5, A1 should be 100
if cell value in B1 is between 5-10, A1 should be 200
if cell value in B1 is between 10-20, A1 should be 300
and so on.

How do I write a formula in A1 to make this calculation?