
theorem Th363:
Sum digits(220,10) = 4
proof
  thus Sum digits(220,10) = Sum <%0,2%>+Sum <%2%> by Th362,AFINSQ_2:55
  .= (0 + 2) + Sum <%2%> by AFINSQ_2:54
  .= 2 + 2 by AFINSQ_2:53
  .= 4;
end;
