
theorem Th1008:
Sum digits(1196,10) = 17
proof
  thus Sum digits(1196,10) = Sum <%6,9,1%>+Sum <%1%> by Th1007,AFINSQ_2:55
  .= Sum <%6,9%> + Sum <%1%> + Sum <%1%> by AFINSQ_2:55
  .= (6 + 9) + Sum <%1%> + Sum <%1%> by AFINSQ_2:54
  .= (6 + 9 + 1) + Sum <%1%> by AFINSQ_2:53
  .= 16 + 1 by AFINSQ_2:53
  .= 17;
end;
