Deduction

The tax agent allowed the deduction.

That was a brilliant deduction. I did not expect you to solve the mystery so quickly.

The program allows pre-tax deduction of the cost of a monthly transit pass.

Without an order from the commander, no one must dare to bring hay, matting, straw, or other such flammable items onto the ship, under penalty of a fine, officers subject to deduction of a month's salary, and enlisted men to be punished by flogging at the mast.

Using his uncanny powers of deduction and the latest in high-tech gadgetry, Agent 86 never seems to get it quite right.

Production costs of the so called $100 laptops are actually around $188. And for two weeks in November, North Americans will be able to buy two for about $400. The plan announced earlier this week is called "Give One Get One." For every laptop bought, one is shipped to a child in the developing world. The buyer gets a $200 tax deduction. The computers can be hand cranked and charged with solar power. That led one boy in a focus group to say they even prevent global warming.

But instinct is something which transcends knowledge. We have, undoubtedly, certain finer fibers that enable us to perceive truths when logical deduction, or any other willful effort of the brain, is futile.

Near-synonyms: extract, reduction; see also Thesaurus:decrement

standard deduction

You might want to donate the old junk and just take the deduction.