
theorem Th593:
Sum digits(2640,10) = 12
proof
  thus Sum digits(2640,10) = Sum <%0,4,6%>+Sum <%2%> by Th592,AFINSQ_2:55
  .= Sum <%0,4%> + Sum <%6%> + Sum <%2%> by AFINSQ_2:55
  .= (0 + 4) + Sum <%6%> + Sum <%2%> by AFINSQ_2:54
  .= (0 + 4 + 6) + Sum <%2%> by AFINSQ_2:53
  .= 10 + 2 by AFINSQ_2:53
  .= 12;
end;
