IF function

IF is probably the most used function in calculators, so a good one to start with

IF(condition, value_if_true, value_if_false)

IF(2>1, 100, 200) will return 100, because 2 is greater than 1.

IF(@NumberQuestion > 20, @SliderQuestion, 0)

The formula above will show:
the value of the SliderQuestion when the NumberQuestion is greater than 20
and
0 when the NumberQuestion is less than or equal to 20.

You can use the IF function together with other functions like OR, AND:

IF( AND(@Age >= 30, @Age =< 50), @Price * 2, @Price )

This formula will double the price for people between the ages of 30 and 50.

Multiple conditions

Let's calculate the final price like this: If the Age is 30, the price is 100, if the Age is 31 to 50, the price is 200.

There are two ways to achieve this. One is with multiple separate IF functions:

IF(@Age = 30, 100, 0) + IF(AND(@Age>=31, @Age<=50), 200, 0)

The other is with the IFS function