
theorem Th1232:
Sum digits(2925,10) = 18
proof
  thus Sum digits(2925,10) = Sum <%5,2,9%>+Sum <%2%> by Th1231,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%9%> + Sum <%2%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%9%> + Sum <%2%> by AFINSQ_2:54
  .= (5 + 2 + 9) + Sum <%2%> by AFINSQ_2:53
  .= 16 + 2 by AFINSQ_2:53
  .= 18;
end;
