Tennis is a sport usually played between two players (singles) or between two teams of two players each (doubles). Each player uses a racket that is strung to strike a hollow rubber ball covered with felt over a net into the opponent's court. Object of the game is to play the ball in such a way that the opponent is not able to play a good return. Tennis is an Olympic sport and is played at all levels of society at all ages. The sport can be played by anyone who can hold a racket, including people in wheelchairs.

The modern game of tennis originated in Birmingham, England in the late 19th century as "lawn tennis" which has close connections to various field/lawn games as well as to the ancient game of real tennis. Up to then, "tennis" referred to the latter sport: for example, in Disraeli's novel Sybil (1845), Lord Eugene De Vere announces that he will "go down to Hampton Court and play tennis. As it is the Derby [classic horse race], nobody will be there". After its creation, lawn tennis spread throughout the upper-class English-speaking population before spreading around the world.

Casio Computer Co., Ltd. (カシオ計算機株式会社, Kashio Keisanki Kabushiki-gaisha^?) is a multinational electronics manufacturing company headquartered in Shibuya, Tokyo, Japan. Its products include calculators, mobile phones, cameras, musical instruments and watches. It was founded in 1946, and in 1957 released the world's first entirely electric compact calculator.

Casio was established in April 1946 by Tadao Kashio, an engineer specializing in fabrication technology. Kashio's first major product was the yubiwa pipe, a finger ring that would hold a cigarette, allowing the wearer to smoke the cigarette down to its nub while also leaving the wearer's hands free. Japan was impoverished immediately following World War II so cigarettes were valuable, and the invention was a success.

After seeing the electric calculators at the first Business Show in Ginza, Tokyo in 1949, Kashio and his younger brothers used their profits from the yubiwa pipe to develop their own calculators. Most of the calculators at that time worked using gears and could be operated by hand using a crank or using a motor (see adding machine). Kashio possessed some knowledge of electronics, and set out to make a calculator using solenoids. The desk-sized calculator was finished in 1954 and was Japan's first electro-mechanical calculator. One of the central innovations of the calculator was its adoption of the 10-key number pad; at that time other calculators were using a "full keypad", which meant that each place in the number (1s, 10s, 100s, etc...) had nine keys. Another innovation was the use of a single display window instead of the three display windows (one for each argument and one for the answer) used in other calculators.

Massive is an adjective related to mass.

Massive may refer to: