
theorem Th1364:
Sum digits(4825,10) = 19
proof
  thus Sum digits(4825,10) = Sum <%5,2,8%>+Sum <%4%> by Th1363,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%8%> + Sum <%4%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%8%> + Sum <%4%> by AFINSQ_2:54
  .= (5 + 2 + 8) + Sum <%4%> by AFINSQ_2:53
  .= 15 + 4 by AFINSQ_2:53
  .= 19;
end;
