hello this is professor sampson again and we are going to be working on another calculator function today we will be

working on finding the LCM in the calculator LCM which you should know let me move this down a little is the least common multiple and my handwriting is horrible but the least common multiple and the least common multiple of course

is multiples or the numbers that you get when

you multiply like two times two is four etc. etc. so

least common multiple so one way to list multiples is to just list the

numbers so let’s say of we wanted the LCM between 12 and 15 normally we would take and list the multiples of

12 and we would keep going 12 times one is 12 times two is 24 and we would keep going

36 48 60 72 and I could keep going and going

and going let me move this in a little bit then the next set if I want to list the multiples of

15 I would list 15 30 45 60 and then I could keep going and going and going but I’ve run into the least common

multiple that they have in common which is sixty so that’s my LCM so my LCM between 12 and 15 is sixty well what if I wanted to find the LCM

between 16 and 18 right what is that and then I

start of 16 then I have 16 32 48 64 80 I’m gonna stop right there and then I’m

gonna list the ones with the multiples of 18 18 36 54 72 90 and look I’ve already gone

five in and I still don’t have a LCM so we’re going to use a calculator

because we don’t want to use the list method and be listing these for a long time for

a large numbers so we’re gonna of course turn our calculator on to find the LCM in your calculator you are going to hit the Math button

which is down here under 2nd alpha then math so you’re gonna hit the Math key and you should have seen the GCF video if you looked at that it’s going to be the same step math

then you go over to number which is NUM see you have to go over hit the over

button here to number and if you look down it’s going

to be number 8 GCF was nine its going to be

number eight so you can hit just the number 8 when we hit number eight we give them

and what we do is we put a comma between the two numbers so we are gonna write 16 comma 18

close your parenthesis the comma is on top of the 7 hit enter and then you have 144 so the LCM between 16 and 18 is 144 as you see I would have had a long way

to go until I got so 144 so that’s why we want

to use are calculator to make this the most expeditious process as possible alright so if I did do 12 and 15 so now you

can go and do 12 and 15 math num and then number 8 and then you put in 12 Comma 15 and then you get sixty which is much

faster than us listing all those factors and

remember we may have larger numbers like the one that we just did between 16

and 18 where the LCM was 144 the last part in this video is how are we gonna find the LCM of three numbers so let’s say we wanted to

find the LCM of 6 4 and 10 how we gonna find the LCM of that you

cannot put three numbers in straight across under LCM so what you’re gonna have to do is you’re

going to do your normal with 6 and 4 so you’re going to go math over to num and then you’re going to

hit number 8 you gonna put it 6 comma 4 as you see

me doing here right and that gave you 12 then your

next step is you’re gonna find the LCM between 12 and him so you’re going to go again math over to number down to eighty and now

you gonna put in the last number please Oakley you calculate is right if you

don’t remember 12 the last number which is 10 here and the number that you

have when you calculate which is 12 so 12 comma 10 and that’s gonna give you your health

p.m. I V 3 which is sixty right so that’s how you

find be how p.m. in your TI 83 or 84 plus graphing calculator