FOIL
Units & Measurements abbreviation · Math
| Stands for | First, Outer, Inner, Last |
|---|---|
| Categories | Units & Measurements |
FOIL stands for First, Outer, Inner, Last, a math abbreviation.
Mnemonic for multiplying two binomials: multiply the first terms, the outer terms, the inner terms and the last terms, then add. (x + 3)(x + 2) = x² + 2x + 3x + 6 = x² + 5x + 6.
Example: Use FOIL to expand (2x − 1)(x + 4) = 2x² + 8x − x − 4 = 2x² + 7x − 4.
Usage notes
FOIL is simply the distributive property applied twice, and it only works for two binomials; longer polynomials require multiplying every term by every term, often with a box or area model. Some teachers discourage it for that reason. Factoring a quadratic is sometimes described as "reverse FOIL".
Related abbreviations
More math abbreviations
- CPCTC – Corresponding parts of congruent triangles are congruent
- csc – Cosecant
- deg – Degree (angle)
- det – Determinant
- dim – Dimension
- exp – Exponential function
- FTC – Fundamental theorem of calculus
- GCD – Greatest common divisor
- GCF – Greatest common factor
- HCF – Highest common factor
- HL – Hypotenuse-Leg (congruence)
- iff – If and only if