
theorem Th242:
Sum digits(255,10) = 12
proof
  thus Sum digits(255,10) = Sum <%5,5%>+Sum <%2%> by Th241,AFINSQ_2:55
  .= (5 + 5) + Sum <%2%> by AFINSQ_2:54
  .= 10 + 2 by AFINSQ_2:53
  .= 12;
end;
