Monday, January 26, 2009
DCM202 Challenging Problems (1)
The problem is to find the tens digit when 2 is multiplied 2009 times. Most of the students were able to solve simpler problems to see a pattern. A strategy suggested was to try simpler cases until we get the same digit for the tens and ones digit. I was glad I gave the students time to establish the fact that the pattern will definitely repeat. That means they were expected to be able to explain the pattern. I felt that it was insufficient for students to solve the problem based on pattern observation alone. They should be able to show that the pattern is guaranteed.