Prime numbers | Factors and multiples | Pre-Algebra | Khan Academy

What does it mean to be a prime number? Let's progress though some whole numbers and ask ourselves if they meet the criteria. What is the criteria you ask? Watch.

Missed the previous lesson?

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!

About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

For free. For everyone. Forever. #YouCanLearnAnything

[kpzcbttp]

Thank you so much. I understand it now. I am 62 and I am trying to learn some of the stuff that I didn't quite understand when I was at school. My next step is algebra. Its not that I was stupid, as I was fine at other mathematics, it was the fact that the teacher we had for algebra was absolute rubbish at teaching. The whole class could not grasp what she was on about and we thought we were the ones that were thick. In those days (1966 in Scotland) they marked your work out of 100 and I can remember I got full marks for arithmetic and 80 out of 100 for geometry and a dismal  5 out of 100 for algebra, the rest of the class was just as bad. The class also excelled in chemistry, botany and biology but we still thought it was our fault that our algebra was a disgrace. Than God I didn't need algebra for my job as a personnel manager. I am retired now so I'm doing some more learning to prove a point to myself. Thank you for your help and your wonderful way of explaining things.

[boldaer]

5:39 "We now know you could divide atoms, and, actually, if you do, you might create a nuclear explosion."

I lolled so hard. That made my day.

[JYT..]

You are a LIFE saver! My teacher was teaching me about this in online school and after math class i quickly looked up what are prime numbers and then i found your video! Thank you!

[anhelicaalvarez]

You are awesome 👏🏼 You taught me a lot!!!
Thanks to you I got my GED and I am now studying to become a nurse 👩‍⚕️

[mmq]

i am a sophomore in college and i quite literally have never understood primes. (mostly because I never cared to) but I got a programming assignment to make a program that checks if a number is prime and I was having a ton of trouble understanding how to check if a number is prime by theory. A bunch of videos were useless in explaining the topic to me but you hit the nail on the head. Nice. Thanks

[mohammedhuzaifa]

Thanks man 👍🤘🤙

It made me easy after it 😊😁

Love you bye 🤭❤😍😘🥰

[jesselovell]

Thanks for the video I am currently learning math for the first time because in school I didn't pay attention your vise helped a lot

[sheepphic]

You guys should do an abstract algebra course. It's really hard to find introductory info on the subject online, and it's essential for basically all of modern number theory

[andrewa]

You my good sir, Khan, are a hero! Thank you for teaching me prime numbers that others couldn't teach.

[TheSupermodel]

Wow! Thank you for clarifying that. I didn't really get it the way it was explained in class, but you have definitely simplified this for me. Thank you. Your videos and teaching style usually make math really simple for me:)

[kermit]

Wow I completely forgot about this...thanks for the refresh.

[piratelife]

Dude this is so cool!! Thank you for your videos man I'm learning so much! Peace and prosperity to you !

[capteddie]

I'm enjoying your videos quite a bit. I'd love to see more info about prime numbers like different tests for prime numbers. Thanks!

[aronbetterfr]

*who is here because they didnt listen to class*

[BestUsernameEvaaaa]

I love this guy!!! thank you thank you thank you!!! i have been struggling with prime numbers for long i can't thank you enough!!!! :)

[coolrobos]

Thanks a lot... I searched many videos but didnt find them comfortable. Then I searched for Khan Academy and got it Thank you soo much. Jazakallahu Khairan.. ;)

[Celoov]

What if we search for the numbers that can only be build by primes. Like 51. It's build by 3 times 17, which are both primes. Plot these evolved-primes (51 etc.) into the same graph that can show how numbers and primes turns into spirals and later strings when viewing from a bigger perspective.

[ngocgiauhuynh]

thank you for this video, i was watching other vids and have no idea what's prime number is and this video helped me understand it well.

[ObsidianSword-We-Da-Bomb]

what's the drawing program you use

[melissaramirez]

this video helped me so much I understand prim numbers now thank you