During the public lesson study day, four different lessons were taught, and
School Number Two teachers, Greenwich Japanese School teachers, and other
invited educators went into the classrooms to watch. In one lesson, secondgraders
were introduced to multiplication with the problem "I bought five
Kit-Kat bars, and each one has four pieces. How many pieces do we have? Do
we have enough for everyone to have a piece?'" Students represented and
solved the problem using various strategies, and the teacher asked students to
share these on the board and explain them. I found myself surprised to hear
these young students thoughtfully explain their solution methods and explore
the connections among them-for example, why skip-counting by 4's amounts
to the same total as adding groups of four. When a second problem was
assigned, observers could gauge how students' thinking about multiplication
had progressed over the course of the lesson.