
theorem Th1034:
Sum digits(1541,10) = 11
proof
  thus Sum digits(1541,10) = Sum <%1,4,5%>+Sum <%1%> by Th1033,AFINSQ_2:55
  .= Sum <%1,4%> + Sum <%5%> + Sum <%1%> by AFINSQ_2:55
  .= (1 + 4) + Sum <%5%> + Sum <%1%> by AFINSQ_2:54
  .= (1 + 4 + 5) + Sum <%1%> by AFINSQ_2:53
  .= 10 + 1 by AFINSQ_2:53
  .= 11;
end;
