
theorem Th116:
Sum digits(104,10) = 5
proof
  thus Sum digits(104,10) = Sum <%4,0%>+Sum <%1%> by Th115,AFINSQ_2:55
  .= (4 + 0) + Sum <%1%> by AFINSQ_2:54
  .= 4 + 1 by AFINSQ_2:53
  .= 5;
end;
