I've know the syntax IndexNumber that gives "the index of the array value within the Variable Array ", so that IndexNumber returns the corresponding Variable in an array
But how can I do to have my Variable in an array to return its IndexNumber ?
For example below
I would like when user select 10 to return its index 1, 20 to return its index 2 ...
I've made some research but have to clue about how to work this way