
theorem Th787:
Sum digits(770,10) = 14
proof
  thus Sum digits(770,10) = Sum <%0,7%>+Sum <%7%> by Th786,AFINSQ_2:55
  .= (0 + 7) + Sum <%7%> by AFINSQ_2:54
  .= 7 + 7 by AFINSQ_2:53
  .= 14;
end;
