### Divisibility Fold It Up!

After pretesting our number theory and fractions chapter, I learned that very few students know the divisibility rules (many know 2, 5, and 10). So today we discussed the different rules and worked on our Divisibility "Fold It Ups."

The Fold It Up also includes the definitions of prime and composite, because the divisibility rules can help students to determine whether a number is prime or composite.

After folding on the vertical line, students cut on the horizontal lines, and then wrote the rules on the inside.

I've found that some students like to write on the reverse side of the flaps, while others like to write on the blank, "bottom" side, so I didn't tell them which part to write on, just that the rule had to be with the correct number! They also had to find a place to include our examples. It was interesting to see how students designed their Fold It Up. I made a few different examples of the inside, based on the way various students designed theirs (I made them for the absent students).

Here's hoping that they use these when doing their homework tonight!