One sql statement to subtract and update a field value

I would like to keep track of inventory and update it as the products are moved. Here is a sample

Inventory Table:

Sample data

InventoryID    InventoryName  Quantity
1                  Printer             10
2                  Mouse             12
3                  Monitor             9

How do I write a single query that decreases the quantity of, say, mouse

UPDATE Inventory
   SET Quantity = Quantity - 1
 WHERE InventoryID = 2



didnt think it was possible to say Quantity = Quantity - 1

we learn everyday!