Hide or show fields on a form based on a number of a dropdown menu

[SingularFact]

I have an Adobe pdf with some fields of a form. One of the fields is a dropdown with numbers 1 to 10. The idea is that there is one signature and date shown by default and I need to aff more if the number on the dropdown is higher than 1.... 2 signature+date, 3 signature+date, etc. 

Signeture and date are obviously 2 fields.

Can anyone help please?

thanks

[Nesa Nurani]

If your fields are named "Signature1-10" and "Date1-10" you can use this as custom calculation script of dropdown field:

for(var i=1; i<=10; i++){
if(Number(event.value) >= i){
this.getField("Signature"+i).display = display.visible;
this.getField("Date"+i).display = display.visible;}
else{
this.getField("Signature"+i).display = display.hidden;
this.getField("Date"+i).display = display.hidden;}}

[SingularFact]

Thanks! To promt the action is "Field activated" what I should mark? (sorry image is in spanish but you can reply in english). 

[SingularFact]

Sorry I used a checkbox not a dropdown. Can I send you the document and paypal you to do it?