Here's a nice post on using place value cards to help students understand decomposing numbers and expanded form. Includes a link to a set of place value cards. Could change colors to go with Math-U-See.
My teacher uses a Noise Meter similar to this one. The Noise Meter is a cool way to remind students the correct noise level that they should be using! You just use the paper clip and move it to the appropriate noise level the students should be using.
Fall Crafts for Kids: Sponge Painted Owl Art Project with free owl template! This autumn activity can be used as process art for preschoolers or a way to work on math patterns in kindergarten and first grade!