
theorem Th292:
Sum digits(133,10) = 7
proof
  thus Sum digits(133,10) = Sum <%3,3%>+Sum <%1%> by Th291,AFINSQ_2:55
  .= (3 + 3) + Sum <%1%> by AFINSQ_2:54
  .= 6 + 1 by AFINSQ_2:53
  .= 7;
end;
