hey everyone it's kaylee this is the first video about greatest common factor we're
going to learn what the greatest common factor is and one method for finding it
sam has 10 chocolate bars and 20 candies to give out to his friends what is the largest number of
friends sam can give a bag of candy to if each bag of candy has the same contents and no candy
is left over well if sam had just one friend she would get all 20 candies and 10 chocolate bars
what if sam had 2 friends each friend could get 10 candies and 5 chocolate bars
now what if sam had 5 friends each friend would get four candies and
two chocolate bars do you think sam could have even more friends to share this candy with
to solve sam's candy problem we need to learn about the greatest common factor
maybe you've seen this before as gcf do you know what it means a greatest common factor
of two numbers is the greatest number that is a factor of both
okay that sounds like really confusing but let's work through this together and we'll figure it out
so sam's candy question is really asking what is the greatest common factor
between 10 and 20 well the word factor really just means divisor
so what we're really asking is what is the largest number that both 10 and 20 can be
divided by we can find this by listing all of the factors for 10 and 20. for 10
we know 1 times 10 is 10 and 2 times 5 is equal to 10. and for 20 we know 1 times 20 is equal to 20
2 times 10 is equal to 20 and 4 times 5 is equal to 20. so all of these numbers here are our
factors for 10 and 20. so let's write these out as lists so for 10 i have 1 2 5 and 10 and for 20
i have 1 2 4 5 10 and 20. so let's take a good look at these two lists we need to find the
largest number that is in both of these lists it looks like they both have a 1 they both have a 2
they both have a 5 and they both have a 10. and we know that 10 is the largest number that's matching
in these two lists so that tells us that the greatest common factor or the gcf of 10 and 20 is
going to be equal to 10 and that would mean that sam can give 10 friends the same amount of candy
each friend would get two candies and one chocolate bar now you know what the greatest
common factor is and one method for finding it join me in the next video called greatest common
factor prime factorization to learn another method for finding the greatest common factor