Multiples and factors. Prime numbers
First and Second Year of Secondary Education

Highest Common Factor.

The highest common factor of several natural numbers is the largest number that is the factor of all of them at the same time.

  Esta unidad interactiva requiere la máquina virtual de Java J2RE.

Calculate mentally the highest common factor of these two numbers, type it in the control box below and hit Enter.

- If you need a hint, click on the up and down triangles above and you will see the prime factor decomposition of each number, but in that case the message CONGRATULATIONS will have another colour.
- Every time you click on Init, two other random numbers will appear. Write down the accuracy and error rate in 20 of these exercises.

  Eduardo Barbero Corral
Spanish Ministry of Education. Year 2007

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