Least common multiple exercise: 3 numbers | Factors and multiples | Pre-Algebra | Khan Academy

This least common multiple example gives us 3 numbers from which to find the lcm. This is a challenge, but fun. Do it with us!

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Pre-Algebra on Khan Academy: No way, this isn't your run of the mill arithmetic. This is Pre-algebra. You're about to play with the professionals. Think of pre-algebra as a runway. You're the airplane and algebra is your sunny vacation destination. Without the runway you're not going anywhere. Seriously, the foundation for all higher mathematics is laid with many of the concepts that we will introduce to you here: negative numbers, absolute value, factors, multiples, decimals, and fractions to name a few. So buckle up and move your seat into the upright position. We're about to take off!

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[ashleydavis]

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[lizbethruiz]

This helped me a lot I was doing homework and I forgot how to do it I found this video and it really helped thanks so much

[sofyj]

I have an account in Khan and I had a D+ in math (don't make fun of me) and now I have a A- and that was in 2 weeks because or your help Salman. Thank you so much. (my teacher loves you).

[kidswithfunally]

I watched this vid 3 times I got out of school until Friday when I got an A+ on my test. and thx

[michaelsmitten]

This may be an issue between English English and American English, but we are looking at the LOWEST common multiple. Least, over here means less of or fewer, not lowest, in my opinion. LCM stands for Lowest Common Multiple of two or more numbers

[Junkkno.]

East or weast Khan academy is the best

[erinarcos]

thank you so much this helped me with my homework😋

[wisemage]

If factors show up multiple times in a tree you need to multiply them repeatedly based on which tree had the most occurrences of each factor. That didn't happen in this example, though; but if you're factoring something in the triple digits it probably will.

[natalieshawnaceemariewardf]

👐👏Oooooh!!! Now, this makes a lot more sense 😱thank you so much!!!😁😅

[haileyhodgson]

What if there is a number like 4 would u need to do 2x2 and if u have like the numbers 4and 6 would u have to do 2x2x3? And this was very helpful thx

[Sneakykiller]

its really helping me in everything its awesome

[AwkwardAndAwesome]

I'm reviewing basic math right now because I have to take a test soon so that I can go back to school (yay!). I remember doing all of this in school and I just can't believe that all those years I was figuring out least common multiples the long way. >.< Why do they not teach you these little shortcuts in school?!

[Vanessa-gpzg]

I was trying to race you to do the problem the whole time😂

[RBIDPNGUIN]

Cheers mate, this is the best explanation so far.

[SidraBhatti]

This was very helpful and got me through alot of math

[williamwilting]

If you're calculating the LCM of every natural number from 1 to n, is it then actually always correct to calculate it with LCM=n!÷2? I tried this with n being a small number, but I'm not sure if it works for much larger numbers as well.

[Kami]

lcm of (70, 49, 35) by common multiple method please rply fast.

[nimrahakhtar]

this is so awesome. i finally got it! thanks! by the way  what software do u use?