
theorem Th1146:
Sum digits(1450,10) = 10
proof
  thus Sum digits(1450,10) = Sum <%0,5,4%>+Sum <%1%> by Th1145,AFINSQ_2:55
  .= Sum <%0,5%> + Sum <%4%> + Sum <%1%> by AFINSQ_2:55
  .= (0 + 5) + Sum <%4%> + Sum <%1%> by AFINSQ_2:54
  .= (0 + 5 + 4) + Sum <%1%> by AFINSQ_2:53
  .= 9 + 1 by AFINSQ_2:53
  .= 10;
end;
