
theorem Th932:
Sum digits(138,10) = 12
proof
  thus Sum digits(138,10) = Sum <%8,3%>+Sum <%1%> by Th931,AFINSQ_2:55
  .= (8 + 3) + Sum <%1%> by AFINSQ_2:54
  .= 11 + 1 by AFINSQ_2:53
  .= 12;
end;
