Definition: Allowably tax deductions reduce the tax liability for an individual or business.
Advice: Here's an example of how a tax deduction works:
Sally is a teacher who made $45,000 last year. She incurred $250 in expenses to stock her classroom and this is an allowable deduction. When deducted from her income, her new taxable income is $44,750. Deducting this $250 saved her $62.50 in taxes ($250 * 25%).