
theorem Th262:
Sum digits(442,10) = 10
proof
  thus Sum digits(442,10) = Sum <%2,4%>+Sum <%4%> by Th261,AFINSQ_2:55
  .= (2 + 4) + Sum <%4%> by AFINSQ_2:54
  .= 6 + 4 by AFINSQ_2:53
  .= 10;
end;
