
theorem Th913:
Sum digits(2332,10) = 10
proof
  thus Sum digits(2332,10) = Sum <%2,3,3%>+Sum <%2%> by Th912,AFINSQ_2:55
  .= Sum <%2,3%> + Sum <%3%> + Sum <%2%> by AFINSQ_2:55
  .= (2 + 3) + Sum <%3%> + Sum <%2%> by AFINSQ_2:54
  .= (2 + 3 + 3) + Sum <%2%> by AFINSQ_2:53
  .= 8 + 2 by AFINSQ_2:53
  .= 10;
end;
