
theorem Th1348:
Sum digits(4625,10) = 17
proof
  thus Sum digits(4625,10) = Sum <%5,2,6%>+Sum <%4%> by Th1347,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%6%> + Sum <%4%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%6%> + Sum <%4%> by AFINSQ_2:54
  .= (5 + 2 + 6) + Sum <%4%> by AFINSQ_2:53
  .= 13 + 4 by AFINSQ_2:53
  .= 17;
end;
