
theorem Th615:
Sum digits(2860,10) = 16
proof
  thus Sum digits(2860,10) = Sum <%0,6,8%>+Sum <%2%> by Th614,AFINSQ_2:55
  .= Sum <%0,6%> + Sum <%8%> + Sum <%2%> by AFINSQ_2:55
  .= (0 + 6) + Sum <%8%> + Sum <%2%> by AFINSQ_2:54
  .= (0 + 6 + 8) + Sum <%2%> by AFINSQ_2:53
  .= 14 + 2 by AFINSQ_2:53
  .= 16;
end;
