
theorem Th443:
Sum digits(1140,10) = 6
proof
  thus Sum digits(1140,10) = Sum <%0,4,1%>+Sum <%1%> by Th442,AFINSQ_2:55
  .= Sum <%0,4%> + Sum <%1%> + Sum <%1%> by AFINSQ_2:55
  .= (0 + 4) + Sum <%1%> + Sum <%1%> by AFINSQ_2:54
  .= (0 + 4 + 1) + Sum <%1%> by AFINSQ_2:53
  .= 5 + 1 by AFINSQ_2:53
  .= 6;
end;
