## A bit of Set Theory

Katie and I joined my sister’s Golden Key Russian School – Katie attends and I help out my sister with the math classes.  We hope to write semi-detailed descriptions of the lessons on the school’s blog, but here I will relate some fun activities or amusing anecdotes.

One of the activities at this week’s lesson with the older kids (ages 5-7) was playing with questions that begin “What is there more of…?”  For example, we would ask “What is there more of, lions or animals?” and a reasonable answer would be, “There are more animals because all lions are animals but not all animals are lions.”  For the most part, the kids would give the correct answers and decent explanations (although they would often have to be helped with the wordings), but on occasion their logic would be very amusing.  Here are a few such examples:

There are more butterflies than insects because we see them more often.  (Lucky kid!)

There are more cats than mice because cats eat mice.

There are more frogs than tigers because they are smaller.

There are more toys than balls, because one gets toys as presents for birthdays and holidays.

Some questions led to fun discussions: “What are there more of, bricks or buildings?”  One of the kids said that there were more bricks because a building contains many bricks.  I pointed out that not all buildings are made out of bricks.  However, we decided that enough of them probably were to make the answer still valid.

The answer to “What are there more of, leaves or trees?”seems to be affected by one’s estimate of the number of conifers, and the time of the year.