All the factors are found when the next value is part of a pair that has already been identified. The difference is 3. The 3rd multiple of seven is 7 × 3 = 21. The 4th multiple of six is 6 × 4 = 24.

To be able to find factors and write a number as a product of prime factors, having knowledge of powers and indices is useful. Remember: To find all the factor ... 3 and 10 or 5 and 6.