| Abbreviation | Definition |
|---|---|
| R | Reciprocal |
| R | Rectangle |
| R | Recursive |
| R | Relative |
| R | Relevant |
| R | Renormalization |
| R | Reverse |
| R | Right |
| R | Rounded |
| R | Row |
| RA | Random Average |
| RAF | Rational Algebrae Fraction |
| RAF | Rational Algebraic Fraction |
| RAFF | Raw Actual Final Fractions |
| RAL | RDF ALgebra |
| RAM | Really Amazing Mathematics |
| RAM | Rectangular Approximation Method |
| RAM | Recursive Analog Multiplication |
| RAP | Redundancy Adjustment of Probability |
| RAP | Regression Analysis Program |