
theorem Th354:
Sum digits(836,10) = 17
proof
  thus Sum digits(836,10) = Sum <%6,3%>+Sum <%8%> by Th353,AFINSQ_2:55
  .= (6 + 3) + Sum <%8%> by AFINSQ_2:54
  .= 9 + 8 by AFINSQ_2:53
  .= 17;
end;
