Index - R
| Ratio | Euler.Prelude |
| Rational | Euler.Prelude |
| RealFrac | Euler.Prelude |
| recip | Euler.Prelude |
| reduceTriangle | Euler.Util.TrianglePath |
| rem | Euler.Prelude |
| repetendLength | Euler.Util.Decimal |
| return | Euler.Prelude |
| Right | Euler.Prelude |
| round | Euler.Prelude |
| Row | Euler.Util.TrianglePath |