Worked examples
Two examples
Example 1
List all the factors of 36.
- Walk through the pairs that multiply to 36, starting with 1: 1 × 36, 2 × 18, 3 × 12, 4 × 9, 6 × 6.
- 5 does not go in. After 6, the pairs repeat, so stop.
Answer: 1, 2, 3, 4, 6, 9, 12, 18, 36
Example 2
List all the factors of 28.
- Pairs: 1 × 28, 2 × 14, 4 × 7.
- 3, 5 and 6 do not go in. The next pair would be 7 × 4, a repeat.
Answer: 1, 2, 4, 7, 14, 28
Where this is taught: Quiz 7: Factors, Multiples, and Primes, “Finding every factor: the pair walk”
The drill
Ten problems
How many:
Type the numbers with commas between them, like 1, 2, 4. The order does not matter. Then press Check my answers at the bottom.Write the numbers on the line. The answer key, with the reasoning, is on the last page.