6 — Factors and Prime Numbers

Factors and Prime Numbers

Solution & Explanation · ID: FBC37A56

Question

List all factors of 18.

Hint

Start with 1 and 18, then check which numbers from 2 to 9 divide evenly into 18.

Concept

Factors are numbers that divide evenly into another number. To find all factors, we test each number from 1 up to the given number to see which ones divide evenly.

Show Answer

1, 2, 3, 6, 9, 18

Show Solution
1

Start with 1: 18 ÷ 1 = 18 (no remainder), so 1 and 18 are factors.

2

Try 2: 18 ÷ 2 = 9 (no remainder), so 2 and 9 are factors.

3

Try 3: 18 ÷ 3 = 6 (no remainder), so 3 and 6 are factors.

4

Try 4: 18 ÷ 4 = 4.5 (has remainder), so 4 is not a factor.

5

Try 5: 18 ÷ 5 = 3.6 (has remainder), so 5 is not a factor.

6

We already found 6, and numbers beyond 6 would repeat pairs we've found.

A factor tree diagram showing 18 at the top. Below it are factor pairs connected by lines: (1,18), (2,9), and (3,6). Each pair is enclosed in a box. At the bottom, all factors are listed in order: 1, 2, 3, 6, 9, 18.