Question

Find the greatest common factor for the group of numbers. 20. 12, 24

Answer 1

Search for the numbers that divide all of the given set.

Notice that all three of them can be divided by two:

`\begin{gathered} (20)/(2)=10 \\ (12)/(2)=6 \\ (24)/(2)=12 \end{gathered}`

Therefore, 2 is the first common factor. Now, take the numbers 10, 6 and 12 and repeat the procedure. Notice that all of them are divisible by 2:

`\begin{gathered} (10)/(2)=5 \\ (6)/(2)=3 \\ (12)/(2)=6 \end{gathered}`

Therefore, 2 is the next common factor. Now, take the numbers 5, 3 and 6 and repeat the procedure. Notice that 3 is not divisible by 2 and 5 is not divisible by 3. Since there are no more numbers lower tan 3 that divide all of the numbers, there are no more common factors.

The common factors were 2 and 2. Multiply all the common factors to find the greatest common factor:

`2\cdot2=4`

Therefore, 4 is the greatest common factor of 20,12 and 24.