
theorem Th1340:
Sum digits(4525,10) = 16
proof
  thus Sum digits(4525,10) = Sum <%5,2,5%>+Sum <%4%> by Th1339,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%5%> + Sum <%4%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%5%> + Sum <%4%> by AFINSQ_2:54
  .= (5 + 2 + 5) + Sum <%4%> by AFINSQ_2:53
  .= 12 + 4 by AFINSQ_2:53
  .= 16;
end;
