In this example we have a simple quantity field that allows us to choose any number. As soon as we hit the number 1, a hidden field (that is currently set to be a variable field) will get a new value, in our case this is 10. After that a calculation field will count both the quantity and the variable field together resulting in 11 if the quantity is set to: 1. But if the value is other than 1, it will contain the value of 5. So the result will become 7 when quantity is set to 2.