
theorem Th1134:
Sum digits(1250,10) = 8
proof
  thus Sum digits(1250,10) = Sum <%0,5,2%>+Sum <%1%> by Th1133,AFINSQ_2:55
  .= Sum <%0,5%> + Sum <%2%> + Sum <%1%> by AFINSQ_2:55
  .= (0 + 5) + Sum <%2%> + Sum <%1%> by AFINSQ_2:54
  .= (0 + 5 + 2) + Sum <%1%> by AFINSQ_2:53
  .= 7 + 1 by AFINSQ_2:53
  .= 8;
end;
