
theorem Th207:
Sum digits(352,10) = 10
proof
  thus Sum digits(352,10) = Sum <%2,5%>+Sum <%3%> by Th206,AFINSQ_2:55
  .= (2 + 5) + Sum <%3%> by AFINSQ_2:54
  .= 7 + 3 by AFINSQ_2:53
  .= 10;
end;
