| A | B |
| prime factorization | expressing a composit number as a product of prime numbers. For example, the prime factorization of 63 is 3x3x7 |
| prime number | a whole number greater than 1 that has exactly two factors, 1 and itself |
| ratio | a comparison of two numbers by division. The ratio of 3 to 3 can be written as 2 out of 3, 2:3, or 2/3 |
| rational number | a number that can be expressed as a fraction |
| repeating decimal | a decimal whose digits repeat in groups of one or more. Example: 0.818181... |
| simplest form | a fraction is in simplest form when the GCF of the numerator and the denominator is 1 |
| terminating decimal | a decimal whose digits end. Every terminalting decimal can be written as a fraction with the denominator of 10, 100, 1000, etc. |
| Venn Diagram | a diagram that uses overlapping circles to show how elements among sets of numbers or objects are related |