Deduction

Deduction may refer to:

Philosophy

 * Deductive reasoning, the mental process of drawing inferences in which the truth of their premises ensures the truth of their conclusion
 * Natural deduction, a class of proof systems based on simple and self-evident rules of inference that aim to closely mirror how reasoning actually occurs

Taxation

 * Tax deduction, variable tax dollars subtracted from gross income
 * Itemized deduction, eligible expense that individual taxpayers in the United States can report on their Federal income tax returns
 * Standard deduction, dollar amount that non-itemizers may subtract from their income

Other uses

 * English modals of deduction, English modal verbs to state how sure somebody is about something.
 * Deduction (food stamps), used in the United States to calculate a household's monthly food stamp benefit goods