
theorem Th1184:
Sum digits(2125,10) = 10
proof
  thus Sum digits(2125,10) = Sum <%5,2,1%>+Sum <%2%> by Th1183,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%1%> + Sum <%2%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%1%> + Sum <%2%> by AFINSQ_2:54
  .= (5 + 2 + 1) + Sum <%2%> by AFINSQ_2:53
  .= 8 + 2 by AFINSQ_2:53
  .= 10;
end;
