
theorem Th1132:
Sum digits(1225,10) = 10
proof
  thus Sum digits(1225,10) = Sum <%5,2,2%>+Sum <%1%> by Th1131,AFINSQ_2:55
  .= Sum <%5,2%> + Sum <%2%> + Sum <%1%> by AFINSQ_2:55
  .= (5 + 2) + Sum <%2%> + Sum <%1%> by AFINSQ_2:54
  .= (5 + 2 + 2) + Sum <%1%> by AFINSQ_2:53
  .= 9 + 1 by AFINSQ_2:53
  .= 10;
end;
