
theorem Th928:
Sum digits(92,10) = 11
proof
  thus Sum digits(92,10) = Sum <%2%>+Sum <%9%> by Th927,AFINSQ_2:55
  .= 2 + Sum <%9%> by AFINSQ_2:53
  .= 2+9 by AFINSQ_2:53
  .= 11;
end;
