Here’s my latest What Do You Notice? poster from a recent Family Math Night event.  The nice thing about these posters is that they’re open-ended which allows for anyone to respond.  For this one, I decided to make a venn diagram.  But I didn’t draw the usual circles.  Instead I drew two hexagons.  This created the rhombus (parallelogram) in the center.

The categories I used for the numbers were even numbers and multiples of 5.  That said, anything appropriate would have been an acceptable answer.  For example, one kindergartner noticed a ‘diamond’.  Another student noticed that 12 x 4 = 48 and 15 x 5 = 75.  And yet another student noticed that the numbers on the left are all multiples of 4; the numbers in the center are all multiples of 10; and the numbers on the left are all multiples of 5.  And check out this observation (which never occurred to me):  The total area of the entire hexagon is 150 square inches so they would put ‘150’ in the middle (although they used the word ‘volume’, I’m pretty sure they meant ‘area’).