This week in one of the elementary math classes, students worked with their homemade number cards 1-30. Each card has all the possible arrays that an number can make. For instance, the 9 card has a 1x9, 9x1, and a 3x3 on it. The 11 card only has a 1x11 and 11x1, while 12 has 1x12, 12x1, 2x6, 6x2, 3x4, and 4x3.

Students worked alone or with a partner to sort (classify) their cards in many ways... even and odd numbers, multiplies of 5s, etc. Eventually students sorted according to the number of arrays each number had, ending up with 3 groups: those numbers with 2 arrays, those numbers with more than 2 arrays, and the third group was for any number that didn't fit either criteria. Can anyone guess what number(s) that might be? Go to the blog and reply to this entry. Let's see who posts the answer first... a student or a parent!