In my classroom I have created a culture where students always stay in there seat unless given permission to be up. These signals alleviated some of the simple questions that students asked by assigning them hand signals. The universal one that all kids know is to raise their hand to ask a question, but I went beyond that.
In this group of 11 X 17 posters I have created hand signal posters for when students want a drink of water, need to sharpen a pencil, need a tissue, go to the restroom, or they need to throw something away. With these signals I can easily give a nod or just say yes and not have to waste classroom instruction time. I hope this helps:D