
theorem Th62:
Sum digits(44,10) = 8
proof
  thus Sum digits(44,10) = Sum <%4%>+Sum <%4%> by Th61,AFINSQ_2:55
  .= 4 + Sum <%4%> by AFINSQ_2:53
  .= 4+4 by AFINSQ_2:53
  .= 8;
end;
