
theorem Th1098:
Sum digits(625,10) = 13
proof
  thus Sum digits(625,10) = Sum <%5,2%>+Sum <%6%> by Th1097,AFINSQ_2:55
  .= (5 + 2) + Sum <%6%> by AFINSQ_2:54
  .= 7 + 6 by AFINSQ_2:53
  .= 13;
end;
