The lessons were both on addition. As the students are the midst of the textbooks, it was not possible for me to know which lessons they were at on the day of the open lesson, I decided to teach lessons which are based on addition but is not part of the textbook lessons.
The purpose of the open lesson is for teachers to understand the fundamenatals of Singapore mathematics curriculum - in particular the big ideas and the problem-solving approach.
In Grade 2, the anchor task is to arrange five consecutive numbers (initially 1-digit numbers and later where the sum is 3-digit)in a cross formation such that the verical sum equals the horizontal sum.
In Grade 3, the anchor task is to make the greatest possible sum (ABCD + EFG) using given digits 1, 2, 3, 4, 5, 7, 8. Sometimes conditions such as less than 500 are given. Another digit is added to make the greatest sum for ABCD + EFGH but the sum has to be less than 10 000.
I also gave a plenary session to parents and teachers at the end of the day.
This is the plenary presentation.