
theorem Th145:
Sum digits(84,10) = 12
proof
  thus Sum digits(84,10) = Sum <%4%>+Sum <%8%> by Th144,AFINSQ_2:55
  .= 4 + Sum <%8%> by AFINSQ_2:53
  .= 4+8 by AFINSQ_2:53
  .= 12;
end;
