Variation: Make cardboard number lines shaped like thermometers (red=neg/black=pos), put in ziplok bag, turn sideways and use slider to count up or down to add/subtract integers . T's First Grade Class: Ziploc Slider Bag Number Lines
Laminate a number ladder, cut small slits in top & bottom & add a pipe-cleaner with a small bead. Use the bead to slide up & down as you complete addition & subtraction problems (",). could do the same thing with a horizontal number line.