Younger kids can learn about subtraction, addition, multiplication, division and decimal operations with the talking calculator at PBS Kids. This animated calculator says the numbers and operations when buttons are selected. For older players, CoolMath has online scientific and graphing calculators. CoolMath provides instructions and problems for students to try out on the graphing calculator, which displays the expressions on a graph alongside the calculator.
Kids can play an interactive Beat the Calculator game, which comes with sample and blank game cards and instructions in a PDF file that can be downloaded from GreatMathGames. Algorithms are called out. Then it is a race between players to see who can find the answer quickest with all the players using calculators. Or it can be played with one player using a calculator and another one using a pencil and paper. Another calculator game offered on this site is the Wipe Out game. Players are given complex formulas that involve skill in application, and the first player to have a zero display on his calculator loses.
Play an assortment of over a dozen calculator games at the website of Dr. Mike's Math Games for Kids. There is a Magical Calculator Birthday Trick, an online version of the "Threes" math trick, a modern rice and chessboard story, a game involving upside-down numbers that look like letters, math golf, a geometry angle quiz and an architect game that uses math and can be played online or in a pencil-and-paper version.
MathPlayground has an online game called Calculator Chaos. It has four levels of play, and players need to calculate answers to be able to help the online cartoon character Justin, who has had some troubles with his own calculator. SuperTeacherWorksheets has printable worksheets full of calculator puzzles that make words when turned upside down. An answer sheet is also provided. Dover Books sells a book full of calculator activities entitled "Calculator Puzzles, Tricks and Games."