
theorem Th1244:
Sum digits(3125,10) = 11
proof
  thus Sum digits(3125,10) = Sum <%5,2,1%>+Sum <%3%> by Th1243,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%1%> + Sum <%3%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%1%> + Sum <%3%> by AFINSQ_2:54
  .= (5 + 2 + 1) + Sum <%3%> by AFINSQ_2:53
  .= 8 + 3 by AFINSQ_2:53
  .= 11;
end;
