Form fields should all equal to 100% but there is no total field to calculate the sum

So they are entering a percentage, such as 34.5 for 34.5%?  What happens if they enter a number >= 100?

What are the field names.

This is a bit tricky, but perhaps the best approach is to use Validation Scripts on each field. This will provide an opportunity to reject the entries on a field by field basis. 

// Validation script on Field 1
// First, reject numbers over 100
if(event.value > 100)
{
    event.rc = false;
    app.alert("Value must be 100% or less");
}
else
{// Test other fields.
    var nSum = Number(event.value) + Number(this.getField("Field2").value) + Number(this.getField("Field3").value);
    if(nSum > 100){
      event.rc = false;
      app.alert("The entry in this field brings the total to greater than 100%");
    }    
}

This could be generalized into a single validation script for all of the fields.