DS (almost 5) has just finished Singapore 1A. He has really taken to it and he amazed me today with a bit of reasoning.

The problem said that someone had 16 objects and gave some away. There were 7 objects left. How many were given away?

He thought for a minute and then said, it must be 9 because 8+8=16 so if I take one from one of the eights to make a 7 and give that one to the other 8 I get 9.

Do you think I should share this kind of thing with his teacher at the conference?