
theorem Th377:
Sum digits(460,10) = 10
proof
  thus Sum digits(460,10) = Sum <%0,6%>+Sum <%4%> by Th376,AFINSQ_2:55
  .= (0 + 6) + Sum <%4%> by AFINSQ_2:54
  .= 6 + 4 by AFINSQ_2:53
  .= 10;
end;
