
theorem Th1326:
Sum digits(4350,10) = 12
proof
  thus Sum digits(4350,10) = Sum <%0,5,3%>+Sum <%4%> by Th1325,AFINSQ_2:55
  .= Sum <%0,5%> + Sum <%3%> + Sum <%4%> by AFINSQ_2:55
  .= (0 + 5) + Sum <%3%> + Sum <%4%> by AFINSQ_2:54
  .= (0 + 5 + 3) + Sum <%4%> by AFINSQ_2:53
  .= 8 + 4 by AFINSQ_2:53
  .= 12;
end;
