
theorem Th483:
Sum digits(1540,10) = 10
proof
  thus Sum digits(1540,10) = Sum <%0,4,5%>+Sum <%1%> by Th482,AFINSQ_2:55
  .= Sum <%0,4%> + Sum <%5%> + Sum <%1%> by AFINSQ_2:55
  .= (0 + 4) + Sum <%5%> + Sum <%1%> by AFINSQ_2:54
  .= (0 + 4 + 5) + Sum <%1%> by AFINSQ_2:53
  .= 9 + 1 by AFINSQ_2:53
  .= 10;
end;
