
theorem Th1016:
Sum digits(1288,10) = 19
proof
  thus Sum digits(1288,10) = Sum <%8,8,2%>+Sum <%1%> by Th1015,AFINSQ_2:55
  .= Sum <%8,8%> + Sum <%2%> + Sum <%1%> by AFINSQ_2:55
  .= (8 + 8) + Sum <%2%> + Sum <%1%> by AFINSQ_2:54
  .= (8 + 8 + 2) + Sum <%1%> by AFINSQ_2:53
  .= 18 + 1 by AFINSQ_2:53
  .= 19;
end;
