I just re-read your scenario and thought of another possibility. You mentioned the total of only the numbers which led me to the possibility that some may contain something besides numbers. If this is the case you solution could be this:
Case(GetRepetition( your field name , 1 ) > 0,GetRepetition( number , 1 ),0) +
Case(GetRepetition( your field name , 2 ) > 0,GetRepetition( number , 2 ),0) +
Case(GetRepetition( your field name , 3 ) > 0,GetRepetition( number , 3 ),0) +
Case(GetRepetition( your field name , 4 ) > 0,GetRepetition( number , 4 ),0) +
Case(GetRepetition( your field name , 5 ) > 0,GetRepetition( number , 5 ),0)
In this we are asking is the value of the repeating field greater than 0 or zero, if so then add to our total. In a case where this field contains a text value, this would equal zero based on the above formula.
I hope this covers it.
Marty