You don't have to worry about running out of batteries on your calculator! You can create your own green calculator that is empowered by alternative energy. 4M Tin Can Calculator Green Science Kit allows you to build a power source for the enclosed calculator with 2 recycled soda cans and pencils. Easy to build, fun to watch, great to learn about electricity and energy, this kids green science kit from Educational Toys Planet will introduce an idea how to make kids' own batteries. Tin Can Calculator Green Science Kit includes a calculator, holder, pencils, screws, wires and detailed assembly instructions.