Question

6 and 15

Answer 1

Answer:

1) 3

2) 30

Step-by-step explanation:

To find the GCF, you find out the (prime) factors of the two numbers in question. For this question, we would find the (prime) factors that go into 6 and 15.

For the number 6, we can get 2 x 3 = 6.

For the number 15, we can get 3 x 5 = 15.

You then underline those factors that you have in common. As you can see, since there is only 1 factor underlined per number, we would have the GCF as 3. On the instance you have more than 1 number underlined, you just multiply them.

Example: 12 and 20

2 x 2 x 3 = 12

2 x 2 x 5 = 20

They both have 2 x 2 in common, so you would get 4 as the GCF.

Moving onto the LCM, I would find this by multiplying each number until i find something similar.

6 x 1 = 6

6 x 2 = 12

6 x 3 = 18

6 x 4 = 24

6 x 5 = 30

15 x 1 = 15

15 x 2 = 30

The number that is underlined is the lowest common number we have when multiplying and going up by 1, so 30 would be our answer.

A faster way you could've solved this is by knowing that you can't multiply 6 and a whole number to get 15, but you can multiply 6 and a whole number to get 30. This, however, is just prior knowledge.