
theorem Th1274:
Sum digits(3625,10) = 16
proof
  thus Sum digits(3625,10) = Sum <%5,2,6%>+Sum <%3%> by Th1273,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%6%> + Sum <%3%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%6%> + Sum <%3%> by AFINSQ_2:54
  .= (5 + 2 + 6) + Sum <%3%> by AFINSQ_2:53
  .= 13 + 3 by AFINSQ_2:53
  .= 16;
end;
