| A | B |
|---|
| Prime numbers | whole numbers whose only factors are 1 and the number itself |
| Composite numbers | whole number with other factors besides 1 and the number |
| A number is divisible by 2 if | it is even |
| A number is divisible by 3 if | the sum of the digits is divisible by 3 |
| A number is divisible by 5 if | it ends in 5 or 0 |
| A number is divisible by 10 if | it ends in 0 |
| To find all the prime factors of a number | construct a factor tree |
| Fundamental Theorem of Arithmetic | every composite number can be written in exactly one way as a product of prime factors |
| To reduce a fraction | cancel out common factors of the top and bottom |
| Equality test for fractions | are cross-products equal? |
| Prime factorization | writing a number as the product of its prime factors |
| Equivalent fractions | represent the same number |
| Simplified fraction | numerator and denominator have only 1 as a common factor |
