
theorem Th1090:
Sum digits(350,10) = 8
proof
  thus Sum digits(350,10) = Sum <%0,5%>+Sum <%3%> by Th1089,AFINSQ_2:55
  .= (0 + 5) + Sum <%3%> by AFINSQ_2:54
  .= 5 + 3 by AFINSQ_2:53
  .= 8;
end;
