Highest Common Factor (HCF) Learn with examples, then test your knowledge!

Highest Common Factor (HCF)

Learn with examples, then test your knowledge!

The Highest Common Factor (HCF), also known as the Greatest Common Divisor (GCD), is the largest number that divides two or more numbers without leaving a remainder.

Examples

Find the HCF of 12, 18 and 24

2	12	18	24
3	6	9	12
	2	3	4

The highest common factor is 2 × 3 = 6

Find the HCF of 24, 36 and 192

2	24	36	192
2	12	18	96
3	6	9	48
	2	3	16

The highest common factor is 2 × 2 × 3 = 12

Find the HCF of 8, 9 and 25

We check for common prime factors (2, 3, 5...). Since none can divide all three numbers, the process stops immediately.

8

9

25

The only number that divides all of them is 1. The HCF is 1, so the numbers are co-prime.

Practice Zone

Now, try it yourself!

Enter numbers, separated by commas:

Calculation Steps:

Final Result:

What are Factors? 🤔 A factor is a number that divides another number perfectly, with no remainder!

What are Factors? 🤔

A factor is a number that divides another number perfectly, with no remainder!

Enter a number to find its factors:

Method 1: Multiplication Pairs

We look for pairs of numbers that multiply to get our target number.

Method 2: Division

We check which numbers divide our target number without a remainder. For example, to check if 3 is a factor of 24, we do 24 ÷ 3. Since the answer is 8 with no remainder, 3 is a factor!

The Factors Are... 🎉

Both methods give us the exact same set of factors!

Total Number of Factors:

A number with this many factors is a: