This creepy Smart board center can be used by your students individually, by student skill groups, or for whole group instruction for increasing number sense in your math classroom! Students choose between two spinning vortex circles. If their choice is correct the vortex will swallow it up! If the student choice is incorrect, the vortex will spit the answer back out onto the page for students to try again. Follow the spider links from page to page as your students increase their conceptual understanding of numbers between 0 and 10!