
theorem Th1354:
Sum digits(4700,10) = 11
proof
  thus Sum digits(4700,10) = Sum <%0,0,7%>+Sum <%4%> by Th1353,AFINSQ_2:55
  .= Sum <%0,0%> + Sum <%7%> + Sum <%4%> by AFINSQ_2:55
  .= (0 + 0) + Sum <%7%> + Sum <%4%> by AFINSQ_2:54
  .= (0 + 0 + 7) + Sum <%4%> by AFINSQ_2:53
  .= 7 + 4 by AFINSQ_2:53
  .= 11;
end;
