Add fun to your math activities with our spiral pi tattoo which spirals with the infinite numbers of pi. It is black and has a very hip design that is not simply for children as it looks scientific and a bit mysterious. Each classroom pack comes with 45 tattoos and each tattoo measures approximately 1.5 inches by 1.5 inches. They can be used as rewards for classroom activities or of course to celebrate PI Day! Each tattoo is individually produced so there is no cutting and the instructions for how to apply them is on the back of every tattoo. You put them on with a damp cloth or wipe and they can be removed with soap and water and scrubbing. Without any scrubbing, they may last up to a week.