
theorem Th1192:
Sum digits(2250,10) = 9
proof
  thus Sum digits(2250,10) = Sum <%0,5,2%>+Sum <%2%> by Th1191,AFINSQ_2:55
  .= Sum <%0,5%> + Sum <%2%> + Sum <%2%> by AFINSQ_2:55
  .= (0 + 5) + Sum <%2%> + Sum <%2%> by AFINSQ_2:54
  .= (0 + 5 + 2) + Sum <%2%> by AFINSQ_2:53
  .= 7 + 2 by AFINSQ_2:53
  .= 9;
end;
