One year olds like dumping and filling. When big sisters are making Lego cars, Carter wants to put all the Legos back in the box. Then he wants to take them back out of the box. In and Out, Empty and Full. These are mathematical ideas of quantity and place. Adults need to give a child the words: In and Out, Empty and Full. We need to be sure to say them out loud when a child is involved in an IN AND OUT EMPTY AND FULL situation, so that a child can say them and understand them. How else can a child figure it out?