
theorem Th56:
Sum digits(11,10) = 2
proof
  thus Sum digits(11,10) = Sum <%1%>+Sum <%1%> by Th55,AFINSQ_2:55
  .= 1 + Sum <%1%> by AFINSQ_2:53
  .= 1+1 by AFINSQ_2:53
  .= 2;
end;
