The Adding Machine (1923) is a play by Pulitzer Prize-winning playwright Elmer Rice. It is a modern drama that tells of the trial, execution, and afterlife of a man called Mr. Zero.

Mr. Zero is a thin, older man who discovers his 25-year career as an accountant is coming to an end, because he is being replaced by an adding machine. In rage, he murders his boss.

Mrs. Zero is his wife, and she is described as an unkempt woman who constantly gossips and complains. She criticizes her husband for being lackluster.

Daisy Diana Dorothea Devore is Mr. Zero's assistant bookkeeper who wears green eyeshadow and paper sleeve protectors. She is a very unhappy woman who has feelings for Mr. Zero, and after his execution, she commits suicide. In the afterlife, they have a brief romantic affair.

The Boss is the strict manager who Mr. Zero kills.

Mr. and Mrs. Six are friends who attend a party at the Zeroes' apartment. They are prejudiced people who dislike feminists, foreigners, Jews, Catholics, and minorities. They are on the jury that convicts Mr. Zero.

The Guide is a man who leads tourists past Mr. Zero's cell, using him as an example of a murderer and selling photos of him.

The Fixer is a pseudo-angelic character whom Mr. Zero asks to prevent his execution, but he refuses and claims Mr. Zero's life has been worthless.

Shrdlu is a ghost who wears glasses and smokes a cigarette. He harbors guilt over killing his mother.

Lieutenant Charles is an immortal who works in the place where the souls of the dead are prepared for reincarnation. While preparing Mr. Zero to be sent back to the living world, he tells him about his past lives.