
theorem Th849:
Sum digits(1562,10) = 14
proof
  thus Sum digits(1562,10) = Sum <%2,6,5%>+Sum <%1%> by Th848,AFINSQ_2:55
  .= Sum <%2,6%> + Sum <%5%> + Sum <%1%> by AFINSQ_2:55
  .= (2 + 6) + Sum <%5%> + Sum <%1%> by AFINSQ_2:54
  .= (2 + 6 + 5) + Sum <%1%> by AFINSQ_2:53
  .= 13 + 1 by AFINSQ_2:53
  .= 14;
end;
