Second graders are given a number to determine if it is odd or even. Many begin to look at the first digit of the number to determine if it is odd or even. I have students use a tool, most will choose counters to see if they can divide the number evenly.
Microsoft Word version: 2_NBT_PropertyOddEven_Problem_Critique
PDF version: 2_NBT_PropertyOddEven_Problem_Critique