
theorem Th703:
Sum digits(3740,10) = 14
proof
  thus Sum digits(3740,10) = Sum <%0,4,7%>+Sum <%3%> by Th702,AFINSQ_2:55
  .= Sum <%0,4%> + Sum <%7%> + Sum <%3%> by AFINSQ_2:55
  .= (0 + 4) + Sum <%7%> + Sum <%3%> by AFINSQ_2:54
  .= (0 + 4 + 7) + Sum <%3%> by AFINSQ_2:53
  .= 11 + 3 by AFINSQ_2:53
  .= 14;
end;
