A factor is a number that divides into another number exactly. A common factor is a number that two numbers can both divide into exactly. The highest common factor is the largest number that divide into two numbers exactly.
Part ofMathsMultiples, factors and primes
The highest common factor (HCF) of two numbers is the largest number that is a factor of both numbers.
For example, the highest common factor (HCF) of \({12}\) and \({18}\) is \({6}\).
What is the HCF of \({16}\) and \({40}\)?
The factors of \({16}\) are \({1}\), \({2}\), \({4}\), \({8}\) and \({16}\).
The factors of \({40}\) are \({1}\), \({2}\), \({4}\), \({5}\), \({8}\), \({10}\), \({20}\) and \({40}\).
So the HCF of \({16}\) and \({40}\) is \({8}\).
