This is a single page 'Trabajo de la mañana' sheet that I use every morning in my class. I print it out as a 30-page booklet and put it into a duotang for my students. Every morning I write in a new 'Número del día', and new numbers to subtract and add by.
This is easy to use and hassle free! My students know to get started on their morning work as soon as they come in through the door :).