Formulas
- Almost everywhere
- Anomaly (physics)
- Antimagic square
- Antisymmetric exchange
- Any-angle path planning
- Approximate max-flow min-cut theorem
- Arbitrary-precision arithmetic
- Archimedean property
- Archimedes number
- Arden Buck equation
- History of the metric system
- Holomorphic Embedding Load-flow method
- Homochirality
- Homogeneous differential equation
- Homography